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Accountable Care Organization
Acronym: ACO

From "ACOs are groups of doctors, hospitals, and other health care providers, who come together voluntarily to give coordinated high-quality care to their Medicare patients."

Acumen Beneficiary Identifier
Acronym: BID

The unique beneficiary identifiation number assigned in CMS data that was previously distributed by Acumen, LLC, as the CMS data distribution contractor. Current data releases do not use this term. The current beneficary identification number on CMS Research Identifiable Files is the CCW Beneficiary ID.

Acute Myocardial Infarction
Acronym: AMI

The Medline Plus web site defines myocardial infarction as "heart attack."

Adjusted Clinical Groups
Acronym: ACG

From Johns Hopkins: "The Johns Hopkins ACG® System is a statistically valid, case-mix methodology that allows healthcare
providers, healthcare organizations, and public-sector agencies to describe or predict a population’s
past or future healthcare utilization and costs."

Affordable Care Act
Acronym: ACA

From the web site: "The comprehensive health care reform law enacted in March 2010 (sometimes known as ACA, PPACA, or “Obamacare”)."

Ambulatory Surgical Center
Acronym: ASC

From the CMS Medicare Claims Processing Manual, 100-04, ch 24, section 10.1: "An ASC for Medicare purposes is a distinct entity that operates exclusively for the purpose of furnishing outpatient surgical services to patients."

American Standard Code for Information Interchange
Acronym: ASCII

From the National Institute of Standards and Technology (NIST):  "ASCII might well be called the first computer interoperability standard. Most modern developments in the computer field, such as the Internet, would not be possible without this underlying code. To this day, all data interchanges start and end as sets of ASCII characters."

Amyotrophic Lateral Sclerosis
Acronym: ALS

Relevance to the Medicare program from "Individuals whose disability is Amyotrophic Lateral Sclerosis (ALS) are entitled to Part A the first month they are entitled to Social Security or RRB disability cash benefits. There is no waiting period."


Medicare Dual Eligibles with full Medicaid benefits are automatically assigned to a Part D plan.


Balanced Budget Act
Acronym: BBA

From the Congressional Research Service: "On May 15, 1997, the President and congressional leaders agreed to a Bipartisan Budget Agreement designed to reduce the budget deficit to zero by 2002. The agreement, subsequently included in the FY1998 Budget Resolution, provided for Medicare savings of $115 billion over the FY1998-FY2002 period." "The BBA 97 achieves the target savings by slowing the rate of growth in payments to hospitals, physicians, and other providers; and by establishing new payment methodologies for skilled nursing facilities, home health agencies, and other service categories."

Basis of Eligibility
Acronym: BOE

From an Office of the Assistant Secretary for Planning and Evaluation (ASPE) glossary: "Eligibility grouping that traditionally has been used by CMS to classify enrollees as children, adults, aged, or disabled."

In the CMS Mediciad data variable, MAX Eligibility Group, the BOE is in position 2 of the variable.

Behavioral Health
Acronym: BH

For term definition see Lexicon for Behavioral Health and Primary Care Integration, chart on document page 48: Behavioral Health Care:  "An umbrella term for care that addresses any behavioral problems bearing on health, including mental health and substance abuse conditions, stress-linked physical symptons, patient activation and health behaviors."

For the description as applies to the Medicaid program see "Behavioral Health Services".

Beneficiary Identification Code
Acronym: BIC

From the ResDAC web site (includes link to code table): "The current beneficiary identification code (BIC) specifies the basis of the beneficiary's elgibility for cash payment programs, mainly Social Security. When the individual qualifies under another person's account (for example, as a spouse or child), the code identifies the type of relationship between the individual and primary beneficiary."

Benign Prostatic Hyperplasia
Acronym: BPH

From the MedlinePlus definition: "An enlarged prostate is also called benign prostatic hyperplasia (BPH)."


NOTE: This term applied to CMS data that was previously distributed by Acumen, LLC, as the CMS data distribution contractor.

See Acumen Beneficiary Identifier.


Cash-Assistance, Medicaid-Only, Fee-for-Service,Beneficiaries with Disabilities
Acronym: CAMOD

Beneficiary grouping category used in algorithms presented in the ResDAC Medicaid workshop segment "Inter- and Intrastate Variation in Medicaid Expenditures."

CCW Beneficiary Identifier
Acronym: Bene_ID

From the ResDAC website: "The unique CCW identifier for a beneficiary. The CCW assigns a unique beneficiary identification number to each individual who receives Medicare and/or Medicaid, and uses that number to identify an individual's records in all CCW data files (e.g., Medicare claims, MAX claims, MDS assessment data).
This number does not change during a beneficiary's lifetime and each number is used only once.
The BENE_ID is specific to the CCW and is not applicable to any other identification system or data source."

Centers for Disease Control and Prevention
Acronym: CDC
Centers for Medicare and Medicaid Services
Acronym: CMS

From the CMS web site:"The Centers for Medicare & Medicaid Services, CMS, is part of the Department of Health and Human Services (HHS)."

Chronic Condition Codes
Acronym: CC

Codes developed by the Chronic Conditions Warehouse to flag common chronic or potentially chronic conditions or diseases. 

Chronic Conditions Warehouse
Acronym: CCW

Refers to the CMS contractor responsible for data distribution

Chronic Disease Score
Acronym: CDS

From the American Journal of Epidemiology: "The Chronic Disease Score is an aggregate comorbidity measure based on current medication use. "

Chronic Illness and Disability Payment System
Acronym: CDPS

From the University of California, San Diego, web site: "The Chronic Illness and Disability Payment System (CDPS) is a diagnostic classification system that Medicaid programs can use to make health-based capitated payments for TANF and disabled Medicaid beneficiaries."

Claim Account Number
Acronym: CAN

From the Social Security Administration: "The claim number is the social security number under which a claim is filed or benefits are paid."

Clinical Modification
Acronym: CM

From the CDC website, International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM): "The National Center for Health Statistics (NCHS), the Federal agency responsible for use of the International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10) in the United States, has developed a clinical modification of the classification for morbidity purposes. "

CMS form 1450
Acronym: UB-04

The CMS1450/UB04 is a uniform billing form used by institutional providers for paper submission of claims. Details on the form and CMS instructions for completion are found in Ch 25 of the CMS Claims processing manual. For electronic submissions institutional providers use the ANSI ASC X12N 837I. CMS Medicare Learning Network, Medicare Billing: Medicare Billing: 837I and Form CMS-1450ANSI

CMS Form 1500

CMS form 1500 is the uniform billing form used by professional providers for paper submission of claims. Chapter 26 of the CMS claims processing manual includes instructions for completion of this form. CMS, Medicare Learning Network, Medicare Billing: 837P and Form CMS-1500

Code of Federal Regulation
Acronym: CFR

Per the National Archive web site: "The Code of Federal Regulations (CFR) is an annual codification of the general and permanent rules published in the Federal Register by the executive departments and agencies of the Federal Government. "


COGNOS is an IBM business intelligence software solution.

The Medicaid Statistical Information System (MSIS) data marts used COGNOS Powerplay

Common Working File
Acronym: CWF

From the CMS Claims Processing Manual, chapter 27, section 10: "The Common Working File (CWF) is the Medicare Part A and Part B beneficiary benefits coordination and pre-payment claims validation system which uses localized databases maintained by designated contractors called ‘CWF Hosts’."

Coordinated Care Plan
Acronym: CCP

From the CMS Managed Care Manual, Chapter 1, section 20.2-Coordinated Care Plans (CCPs): "As defined at 42 CFR 422.4(a)(1), a CCP is a plan that includes a network of providers that are under contract or arrangement with the MA organization to deliver the benefit package approved by CMS."

Core-Based Statistical Area
Acronym: CBSA

From the US Census Bureau: "Core Based Statistical Areas (CBSAs) consist of the county or counties or equivalent entities associated with at least one core (urbanized area or urban cluster) of at least 10,000 population, plus adjacent counties having a high degree of social and economic integration with the core as measured through commuting ties with the counties associated with the core."

Coronary Artery Bypass Graft
Acronym: CABG

From the National Library of Medicine: "CABG is a technique that involves using an artery or vein from elsewhere in the body to bypass the blocked vessels, restoring adequate blood flow to the heart."

Covered stay

A hospital or skilled nursing facility stay that meets the requirements for Medicare coverage.

Critical Access Hospital
Acronym: CAH

CMS has eight criteria for designation as a critical access hospital. Briefly stated:
"- located in a State that has established a State Medicare Rural Hospital Flexibility Program
-designated by the State as a CAH
-located in a rural area
-located either more than 35-miles from the nearest hospital
-Maintain no more than 25 inpatient beds
-Maintain an annual average length of stay of 96 hours or less per patient
-Demonstrate compliance with the CAH CoPs found at 42 CFR Part 485 subpart F
-Furnish emergency care 24/7"

Current Procedural Terminology
Acronym: CPT

From the American Medical Association web site: "Use the Current Procedural Terminology (CPT®) code set to bill outpatient & office procedures."


Data Management Plan
Acronym: DMP

From the ResDAC web site: "Each request for research identifiable data requires a data management plan that outlines the administrative, physical and technical safeguards, and incident response preparedness."

Data Privacy Security Program
Acronym: DPSP
Data Use Agreement
Acronym: DUA

From the ResDAC web site: "The Research Identifiable (RIF) Data Use Agreement (DUA) is a legal agreement between CMS and a requesting organization to ensure that the requesting organization adheres to CMS privacy and security requirements and data release policies for protected health information (PHI) and/or personally identifiable information (PII)."

Date of Birth
Acronym: DOB

From the CMS web site: "Date of Birth".

Acronym: DX

From the Merriam-Webster Dictionary: "a : the art or act of identifying a disease from its signs and symptoms
b : the decision reached by diagnosis a diagnosis of pneumonia"

Diagnostic Cost Group
Acronym: DCG

From the CMS Medicare Managed Care Manual, Chapter 7, section 50: "CMS selected the Principal Inpatient Diagnostic Cost Group (PIP-DCG) model as the risk adjustment method to be implemented in 2000. This model recognizes diagnoses for which inpatient care is most frequently appropriate and which are predictive of higher future costs.
To assist managed care organizations, CMS provided for a gradual phase-in of risk adjusted payment, initially adjusting only a portion of the total payment based on the PIP-DCG methodology - and later the CMS Hierarchical Condition Category (HCC) methodology - with the remainder still adjusted under the pre-BBA method based only on demographic information."

Dual eligible
Acronym: dual

From the CMS web site: “Dual eligible beneficiaries” generally describes beneficiaries eligible for both Medicare and Medicaid.
The term includes beneficiaries enrolled in Medicare Part A and/or Part B and receiving full Medicaid
benefits and/or assistance with Medicare premiums or cost sharing..."

Durable Medical Equiipment Regional Carrier
Acronym: DMERC

Durable Medical Equipment Regional Carriers have been replace by the DME-MACs. From the CMS web site: "The DME MACs process Medicare Durable Medical Equipment, Orthotics, and Prosthetics (DMEPOS) claims for a defined geographic area or "jurisdiction," servicing suppliers of DMEPOS. "

Durable Medical Equipment
Acronym: DME

Durable Medical Equipment  meets four requirements: withstands repeat use; serves a medical purpose, not useful in absence of illness, appropriate for home use. See the CMS Claims Processing Manual, ch 20


See Diagnosis.


Early and Periodic Screening, Diagnostic and Treatment
Acronym: EPSDT

From CMS, "The Medicaid Early and Periodic Screening, Diagnostic, and Treatment (EPSDT) benefit provides
comprehensive and preventive health care services for children under age 21* who are enrolled
in Medicaid."


Emergency Department , see Emergency room.

Emergency Room
Acronym: ER

From the Merriam-Webster dictionary: "a hospital room or area staffed and equipped for the reception and treatment of persons requiring immediate medical care"

Medicare billing for emergency room services is described in the CMS Medicare Claims Processing Manual, Ch 4

Employer Group Waiver Plan
Acronym: EGWP

As applied to Medicare Advantage or Part C plans, from chapter 9, section 10.1,Medicare Managed Care Manual, "CMS has the statutory authority to waive or modify requirements that hinder the design of, the offering of, or the enrollment in, employer/union-sponsored Medicare Advantage (MA) plans."

As applied to the Medcare Prescription Drug program or Part D, from the Medicare Prescription Drug Benefit Manual, chapter 12, section 10.1, "CMS has statutory authority to waive or modify requirements that hinder the design of, the offering of, or the enrollment in, employer/union sponsored standalone prescription drug plans (PDPs)."


From the CMS Glossary: "Detailed data about individual services provided by a capitated managed care entity. The level of detail about each service reported is similar to that of a standard claim form. Encounter data are also sometimes referred to as "shadow claims"."

End Stage Renal Disease
Acronym: ESRD

From the CMS Glossary: "Permanent kidney failure. That stage of renal impairment that appears irreversible and permanent, and requires a regular course of dialysis or kidney transplantation to maintain life."

Enrollment Database
Acronym: EDB

From the Office of the Assistant Secretary for Planning and Evaluation (ASPE): "The Enrollment DataBase (EDB) is the Centers for Medicare & Medicaid Services's database of record for Medicare Beneficiary enrollment information. It is the authoritative source for Medicare beneficiary information, entitlement, etc. The EDB has information on all Medicare beneficiaries, including Social Security Retirement and Disability insurance Beneficiaries, End Stage Renal Disease (ESRD) beneficiaries, and Railroad Retirement Board (RRB) beneficiaries."

Environmental Scanning and Program Characteristics
Acronym: ESPC

 A previously available CMS downloadable Public Use File. The ESPC database housed information on Medicaid and CHIP program characteristics as well as selected environmental factors that are available through other publicly available databases. The final project report is available as a PDF document.



Facilitated enrollment

From the CMS Medicare Prescription Drug Benefit Manual, Chapter 3, section 40.1.4: "CMS auto-enrolls and facilitates enrollment of certain LIS beneficiaries into PDPs. “Auto-Enrollment” is the process that refers to full-benefit dual eligible individuals. “Facilitated Enrollment” is the process that refers to other LIS beneficiaries. The primary differences between the two are the populations and the enrollment effective date."

Federal Financial Particpation
Acronym: FFP

From the Code of Federal Regulation, "Federal financial participation (FFP) means the Federal Government’s share of a State’s expenditures under the Medicaid program."

Federal Fiscal Year
Acronym: FFY

From the glossary of the United States Senate: " The fiscal year is the accounting period for the federal government which begins on October 1 and ends on September 30. The fiscal year is designated by the calendar year in which it ends; for example, fiscal year 2013 begins on October 1, 2012 and ends on September 30, 2013. "

Federal Information Processing Standards
Acronym: FIPS

From Census Bureau: "Standardized system of numeric and/or alphabetic coding issued by the National Institute of Standards and Technology (NIST), an agency of the US Department of Commerce. FIPS codes are assigned for a variety of geographic entities including American Indian and Alaska Native Areas, Hawaiian home lands, congressional districts, counties, county subdivisions, metropolitan areas, places and states. The purpose in using FIPS codes is to improve the use of data and avoid unnecessary duplication and incompatibility in the collection, processing and dissemination of data. FIPS codes were discountinued by NIST in 2005, but the Census Bureau continues to maintain and issue codes for the geographic entities covered."

Federal Medical Assistance Percentage
Acronym: FMAP

From the website: "The Medicaid program is jointly funded by the federal government and states. The federal government pays states for a specified percentage of program expenditures, called the Federal Medical Assistance Percentage (FMAP)."

Federal Poverty Level
Acronym: FPL

From the Office of the Assistant Secretary for Planning and Evaluation (ASPE) web site, "The poverty guidelines are the other version of the federal poverty measure. They are issued each year in the Federal Register by the Department of Health and Human Services (HHS).  The guidelines are a simplification of the poverty thresholds for use for administrative purposes — for instance, determining financial eligibility for certain federal programs.  The poverty guidelines are sometimes loosely referred to as the “federal poverty level” (FPL), but that phrase is ambiguous and should be avoided, especially in situations (e.g., legislative or administrative) where precision is important."

Federally Qualified Health Center
Acronym: FQHC

From the CMS Glossary: "A facility located in a medically underserved area that provides Medicare beneficiaries preventive primary medical care under the general supervision of a physician." and "Health centers that have been approved by the government for a program to give low cost health care. Medicare pays for some health services in FQHCs that are not usually covered, like preventive care. FQHCs include community health centers, tribal health clinics, migrant health services, and health centers for the homeless."

Requirements for certification and links to billing instructions are included in the Medicare Learning Network booklet

Acronym: FFS

From glossary: "A method in which doctors and other health care providers are paid for each service performed. Examples of services include tests and office visits."

Within Medicare, the payment system that directly pays participating providers. Also referred to as “traditional" or "original" Medicare”.

Final Action Claim

From Chapter 4 of the CCW Medicare Administrative Data User Guide: "Health care providers often submit more than one version of a claim for a particular service because they need to revise the information on the initial claim for some reason." "The final action claim is the version of the claim where all adjustments to earlier claims have been resolved and CMS’s final action on the claim is accurately recorded."

Frequently Asked Questions
Acronym: FAQ

From the Merriam-Webster Dictionary: "document (as on a website) that provides answers to a list of typical questions that users might ask regarding a particular subject; also, a question included in such a document, a list of FAQs."



Group Health Organization. See Group Health Plan.

Group Health Plan
Acronym: GHP

From the CMS web site Glossary: "A health plan that provides health coverage to employees, former employees, and their families, and is supported by an employer or employee organization."


Health Effectiveness Data and Information Set
Acronym: HEDIS

 From The National Committee for Quality Assurance (NCQA) web site: "HEDIS is a tool used by more than 90 percent of America's health plans to measure performance on important dimensions of care and service."

Health Insurance Claim number (Medicare)
Acronym: HIC

From the CMS Glossary:"The number assigned by the Social Security Administration to an individual identifying him/her as a Medicare beneficiary. This number is shown on the beneficiary's insurance card and is used in processing Medicare claims for that beneficiary."

The Medicare Beneficiary Identifier is replacing the HICN: "We're removing Social Security Numbers (SSNs) from all Medicare cards. A new Medicare Beneficiary Identifier (MBI) will replace the SSN-based Health Insurance Claim Number (HICN) on the new Medicare cards for Medicare transactions like billing, eligibility status, and claim status."

Health Insurance Prospective Payment System codes
Acronym: HIPPS codes

From the CMS Division of Institutional Claims Processing: "Health Insurance Prospective Payment System (HIPPS) rate codes represent specific sets of patient characteristics (or case-mix groups) on which payment determinations are made under several prospective payment systems."

Health Insuring Organization
Acronym: HIO

Per the United States Government Accountability Office web site for Medicaid Requirements: "HIO are entities that: (1) pay for medical services provided to recipients in exchange for fees paid by state Medicaid agencies; and (2) assume underwriting risks."

Health Maintenance Organization
Acronym: HMO

From the glossary: "A type of health insurance plan that usually limits coverage to care from doctors who work for or contract with the HMO. It generally won't cover out-of-network care except in an emergency. An HMO may require you to live or work in its service area to be eligible for coverage."

Healthcare Common Procedure Coding System
Acronym: HCPCS

From the CMS website:  "For Medicare and other health insurance programs to ensure that these claims are processed in an orderly and consistent manner, standardized coding systems are essential. The HCPCS Level II Code Set is one of the standard code sets used for this purpose. The HCPCS is divided into two principal subsystems, referred to as level I and level II of the HCPCS. Level I of the HCPCS is comprised of CPT (Current Procedural Terminology), a numeric coding system maintained by the American Medical Association (AMA)." "Level II of the HCPCS is a standardized coding system that is used primarily to identify products, supplies, and services not included in the CPT codes, such as ambulance services and durable medical equipment, prosthetics, orthotics, and supplies (DMEPOS) when used outside a physician's office."

Hierarchical Condition Categories
Acronym: HCC

The HCCs are used for risk adjustment in the Medicare Part C and Part D programs, as described in Ch 7 of the CMS Medicare Managed Care Manual.  The CMS Risk Adjustment website offers downloadable files for ICD to HCC code mapping and current year models.

High Blood Pressure
Acronym: HBP

From Medline Plus: "Blood pressure is the force of your blood pushing against the walls of your arteries. Each time your heart beats, it pumps blood into the arteries. Your blood pressure is highest when your heart beats, pumping the blood. This is called systolic pressure. When your heart is at rest, between beats, your blood pressure falls. This is called diastolic pressure." "140/90 or higher is high blood pressure"

Home and Community Based Services
Acronym: HCBS

From the web site for HCBS: "Home and community based services (HCBS) provide opportunities for Medicaid beneficiaries to receive services in their own home or community rather than institutions or other isolated settings. These programs serve a variety of targeted populations groups, such as people with intellectual or developmental disabilities, physical disabilities, and/or mental illnesses."

From the web site for the HCBS Waiver program: "Within broad Federal guidelines, States can develop home and community-based services waivers (HCBS Waivers) to meet the needs of people who prefer to get long-term care services and supports in their home or community, rather than in an institutional setting."

Home Health Agency
Acronym: HHA

From the CMS web site: "A Home Health Agency (HHA) is an agency or organization which: Is primarily engaged in providing skilled nursing services and other therapeutic services;Has policies established by a group of professionals (associated with the agency or organization), including one or more physicians and one or more registered professional nurses, to govern the services which it provides..."

Home Health Covered Services
Home Health Outcome and Assessment Information Set
Acronym: OASIS

From the CMS website: "The Outcome and ASsessment Information Set (OASIS) is a group of data elements that:  Represent core items of a comprehensive assessment for an adult home care patient; and  Form the basis for measuring patient outcomes for purposes of outcome-based quality improvement (OBQI).The OASIS is a key component of Medicare's partnership with the home care industry to foster and monitor improved home health care outcomes and is proposed to be an integral part of the revised Conditions of Participation for Medicare-certified home health agencies (HHAs) ..."

Hospice, Medicare

The Medicare Benefits Policy Manual details the services covered under the hospice benefit.


Identifiable Data File
Acronym: IDF

From the CMS web site: "The Centers for Medicare & Medicaid Services (CMS) makes identifiable data files (IDFs) available to certain stakeholders as allowed by federal laws and regulations as well as CMS policy. IDFs contain protected health information (PHI) and/or personally identifiable information (PII) and CMS is committed to ensuring this information is protected."

These files may also be referred to as "RIF" or "Research Identifiable Files."

Independent Diagnostic Testing Facility
Acronym: IDTF

From the CMS Medicare Learning Network: "An IDTF is a facility that is independent both of an attending or consulting physician’s office and of a hospital."

Initial Coverage Limit
Acronym: ICL

From the CCW Part D Data User Guide: "Initial Coverage Limit for the Part D benefit; also referred to as the coverage gap".

Acronym: IP

From the CMS Glossary: "Health care that you get when you are admitted to a hospital."

Inpatient Rehabilitation Facility Patient Assessment Instrument
Acronym: IRF-PAI

From the CMS web site: "The Inpatient Rehabilitation Facility (IRF) Patient Assessment Instrument (PAI) is the assessment instrument IRF providers use to collect patient assessment data for quality measure calculation and payment determination in accordance with the IRF QRP. Completion of the IRF-PAI is required for each Medicare Part A fee-for-service and Medicare Part C patient discharged from an inpatient rehabilitation facility."

Institutional Review Board
Acronym: IRB

From the Code of Federal Regulation, 21CFR56.102: "Institutional Review Board (IRB) means any board, committee, or other group formally designated by an institution to review, to approve the initiation of, and to conduct periodic review of, biomedical research involving human subjects. The primary purpose of such review is to assure the protection of the rights and welfare of the human subjects. The term has the same meaning as the phrase institutional review committee as used in section 520(g) of the act."

Intermediate Care Facility
Acronym: ICF

From the web site: "Intermediate Care Facilities for individuals with Intellectual disability (ICF/ID) is an optional Medicaid benefit that enables states to provide comprehensive and individualized health care and rehabilitation services to individuals to promote their functional status and independence. Although it is an optional benefit, all states offer it, if only as an alternative to home and community-based services waivers for individuals at the ICF/ID level of care. "

International Classification of Diseases
Acronym: ICD

From the World Health Organization web site: " ICD is the foundation for the identification of health trends and statistics globally, and the international standard for reporting diseases and health conditions. It is the diagnostic classification standard for all clinical and research purposes."

In relation to the Medicare/Medicaid programs, ICD-9 was replaced with the implementation of ICD-10 on Oct 1, 2015.


See  Inpatient.


Kaiser Family Foundation
Acronym: KFF

From the Kaiser Family Foundation website, "Kaiser is a non-profit organization focusing on national health issues, as well as the U.S. role in global health policy. Unlike grant-making foundations, Kaiser develops and runs its own policy analysis, journalism and communications programs, sometimes in partnership with major news organizations.

We serve as a non-partisan source of facts, analysis and journalism for policymakers, the media,  the health policy community and the public. Our product is information, always provided free of charge..."


Length of Stay
Acronym: LOS

From the CMS Glossary: "Length of Stay."

From the CMS Medicare Benefit Policy Manual, Chapter 3, section 20.1, Counting Inpatient Days: "The number of days of care charged to a beneficiary for inpatient hospital or skilled nursing facility (SNF) care services is always in units of full days. A day begins at midnight and ends 24 hours later. The midnight-to-midnight method is to be used in counting days of care for Medicare reporting purposes even if the hospital or SNF uses a different definition of day for statistical or other purposes."

Limited Data Set
Acronym: LDS

From the CMS Limited Data Set File web site: "Limited Data Set Files (LDS) are identical to the previous Beneficiary Encrypted Files, but they have been stripped of data elements that might permit identification of beneficiaries. These files contain beneficiary level health information but exclude specified direct identifiers as outlined in the Health Insurance Portability and Accountability Act (HIPAA Privacy Rule).

Long Term Care
Acronym: LTC

For Medicare: "Long-term care is a range of services and support for your personal care needs. Most long-term care isn't medical care. Instead, most long-term care is help with basic personal tasks of everyday life, sometimes called activities of daily living. Medicare doesn’t cover long-term care (also called custodial care), if that's the only care you need. Most nursing home care is custodial care."

For Medicaid: "...Long term care —health-related care and services (above the level of room and board) not available in the community, needed regularly due to a mental or physical condition. A nursing facility is one of many settings for long-term care, including or other services and supports outside of an institution, provided by Medicaid or other state agencies."

Low Income Subsidy
Acronym: LIS

Under the Medicare Prescription Drug Benefit, plans are required to provide assistance to certain low-income beneficiaries. For details, see Chapter 13 of the Medicare Prescription Drug Benefit Manual.



Maintenance Assistance Status
Acronym: MAS

From the Office of the Assistance Secretary for Evaluation and Planning: "Eligibility grouping traditionally used by CMS to classify enrollees by the financial-related criteria by which they are eligible for Medicaid. MAS groups include cash assistance-related, medically needy, poverty-related, 1115 demonstration waiver, and other."

Managed Care Organization
Acronym: MCO

From the Office of the Assistance Secretary for Evaluation and Planning: "Managed care organizations (including HMOs, PPOs, and PSOs) receive a fixed amount of money per client/member per month (called a capitation), no matter how much care a member needs during that month."

Master Beneficiary Summary file
Acronym: MBSF

From the CCW Medicare Data User Guide, "The CCW has always disseminated files which include data regarding Medicare enrollment." "Currently, the preferred enrollment data file is the MBSF (Master Beneficiary Summary File) that uses the CMS Common Medicare Environment (CME) Database as its source." "Like the original MBSF, the current MBSF using the CME enrollment data file contains a constellation of enrollment and other person-level variables..."

MAX Inpatient
Acronym: MAX IP

From the CCW Medicaid Analytic Extract Files (MAX) User Guide, Chapter 3: "The IP file contains complete stay records for Medicaid enrollees who used inpatient hospital services."

MAX Long Term Care
Acronym: MAX LT

From the CCW Medicaid Analytic Extract Files (MAX) User Guide, Chapter 4: "The LT file includes institutional long-term care (LTC) records for services provided by four types of long-term care facilities: 1) mental hospitals for the aged; 2) inpatient psychiatric facilities for persons under age 21; 3) intermediate care facilities for the mentally retarded (ICF/MR); and, 4) nursing facilities (NF). These records do not include procedure codes. Note that other community-based LTC services (e.g., many home-based and personal care services) are included in the OT file."


See MAX Other Therapy File.

MAX Other Therapy
Acronym: MAX OT

From the CCW Medicaid Analytic Extract Files (MAX) User Guide, Chapter 6 "wide variety of service types are included in the OT file, including physician and professional services, outpatient and clinic, DME, hospice, home health, lab/x-ray and others, which are indicated by the Type of Service codes on the claim.

The OT file contains two major types of records: 1) records for services delivered; and 2) payment records for premiums paid to three types of prepaid managed care plans (which can be identified using the type of service codes)."

MAX Personal Summary
Acronym: MAX PS

From the CCW Medicaid Analytic Extract Files (MAX) User Guide, Chapter 6 "The PS (Persoanl Summary) file contains one record for every individual enrolled during the calendar year represented by the file". "The PS file contains enrollment, including waiver enrollment, demographic, and summary utilization data."

MAX Prescription Drug
Acronym: MAX RX

From the CCW Medicaid Analytic Extract Files (MAX) User Guide, Chapter 6, "This file contains prescribed drugs, over-the-counter drugs and other items dispensed by a free-standing pharmacy. However, there are important exceptions…"


See Medicare.

Medicaid Analytic Extract
Acronym: MAX

From the Medicaid web site: "The Medicaid Analytic eXtract (MAX) data is a set of person-level data files on Medicaid eligibility, service utilization, and payments. The MAX data are created to support research and policy analysis. The MAX data are extracted from the Medicaid Statistical Information System (MSIS)."

Medicaid Analytic Extract (MAX) Provider Characteristics
Acronym: MAXPC

From the CMS web site: "These data files contain useful provider information from the National Plan and Provider Enumeration System (NPPES) and state-specific provider files (when available). They can be easily linked to the provider identification numbers (provider IDs) in MAX..."

Medicaid Enrollee Supplemental File
Acronym: MESF

The Medicaid Enrollee Supplemental File includes two segments with Medicaid enrollee data, the National Death Index (NDI) and the Chronic Conditions Segment.

Medicaid Management Information System
Acronym: MMIS

From the web site: "The Medicaid Management Information System (MMIS) is an integrated group of procedures and computer processing operations (subsystems) developed at the general design level to meet principal objectives." "The objectives of this system and its enhancements include the Title XIX program control and administrative costs; service to recipients, providers, and inquiries; operations of claims control and computer capabilities; and management reporting for planning and control."

Medicaid RX
Acronym: MRX

From the University of California at San Diego web site: "The goals of this project were to update CDPS using recently available national Medicaid data, and to develop a combined diagnostic and pharmacy based risk adjustment model based on CDPS and MedicaidRx. The CDPS update to version 5.0, and the combined model, CDPS-Rx, were developed using data from up to 41 state Medicaid programs for years 2001-2002."

Medicaid Statistical Information System
Acronym: MSIS

From the CMS web site: "The source data for MAX has historically been the Medicaid Statistical Information System (MSIS) data reported from states to CMS."

From the web site: "The Medicaid and Statistical Information System (MSIS) used by the Centers for Medicare and Medicaid Services (CMS) to gather key eligibility, enrollment, program, utilization and expenditure data for the Medicaid and Children's Health Insurance Program (CHIP) has been decommissioned and replaced by T-MSIS. "

Medical Savings Account
Acronym: MSA

From the CMS web site: "A Medicare Medical Savings Account (MSA) plan is a type of Medicare Advantage plan that combines a high-deductible health plan with a medical savings account."

Acronym: MC

From the web site: "Medicare is the federal health insurance program for: People who are 65 or older; Certain younger people with disabilities; People with End-Stage Renal Disease (permanent kidney failure requiring dialysis or a transplant, sometimes called ESRD)."

Medicare Administrative Contractors
Acronym: MAC

From the CMS web site: "A Medicare Administrative Contractor (MAC) is a private health care insurer that has been awarded a geographic jurisdiction to process Medicare Part A and Part B (A/B) medical claims or Durable Medical Equipment (DME) claims for Medicare Fee-For-Service (FFS) beneficiaries."

Medicare Advantage
Acronym: MA

From the Medicare Managed Care Manual, chapter 1,  section 10: "The Balanced Budget Act of 1997 (BBA) (Public Law 105-33) established a new Part C of the Medicare program, known then as the Medicare+Choice (M+C) program, effective January 1999. As part of the M+C program, the BBA authorized CMS to contract with public or private organizations to offer a variety of health plan options for beneficiaries, including both traditional managed care plans (such as those offered by Health Maintenance Organizations (HMOs) under §1876 of the Social Security Act) and new options that were not previously authorized." "The Part C program of Medicare was renamed the Medicare Advantage (MA) Program pursuant to Title II of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA) (Public Law 108-173), which was enacted on December 8, 2003."

Medicare Advantage Part D
Acronym: MA-PD
Medicare Advantage Prescription Drug Plan
Acronym: MA-PD

From the Medicare Prescription Drug Benefit Manual, Chapter 1, Section 10.1:  "There are a number of places in which Part D statutory provisions incorporate by reference specific sections of the Act that govern the Medicare Part C program (also known as the Medicare Advantage, or MA program, and formerly the Medicare+Choice, or M+C, program)."

Medicare Beneficiary Database
Acronym: MBD

From the US Health and Human Services web site: "The primary purpose of this modified system is to provide CMS with a singular, authoritative, database of comprehensive enrollment data on individuals in the Medicare program to support ongoing and expanded program administration, service delivery modalities, and payment coverage options."

Medicare Current Beneficiary Survey
Acronym: MCBS

From the CMS web site: "The Medicare Current Beneficiary Survey (MCBS) is a continuous, multipurpose survey of a nationally representative sample of the Medicare population, conducted by the Office of Enterprise Data and Analytics (OEDA) of the Centers for Medicare & Medicaid Services (CMS) through a contract with NORC at the University of Chicago. The central goals of the MCBS is to determine expenditures and sources of payment for all services used by Medicare beneficiaries, including co-payments, deductibles, and non-covered services; to ascertain all types of health insurance coverage and relate coverage to sources of payment; and to trace outcomes over time, such as changes in health status and spending down to Medicaid eligibility and the impacts of Medicare program changes on satisfaction with care and usual source of care."

Medicare Modernization Act
Acronym: MMA

From the Baylor University Medical Denter Proceedings journal: "The Medicare Prescription Drug, Improvement, and Modernization Act of 2003 was enacted in November 2003 and became effective on January 1, 2006. Two major changes occurred. A prescription drug benefit is now available for seniors and younger persons with disabilities who are covered by Medicare. The managed care program, formerly known as Medicare + Choice, has been redesigned and renamed Medicare Advantage."

Medicare Part A, B, C, D

From the CMS web site, Parts A, B and D: "Medicare has different parts that help cover specific services: Medicare Part A (Hospital Insurance) - Part A helps cover inpatient care in hospitals, including critical access hospitals, and skilled nursing facilities (not custodial or long-term care). It also helps cover hospice care and some home health care. Medicare Part B (Medical Insurance) - Part B helps cover doctors' services and outpatient care. It also covers some other medical services that Part A doesn't cover, such as some of the services of physical and occupational therapists, and some home health care. Medicare Part D (Prescription Drug Coverage) - Medicare prescription drug coverage is available to everyone with Medicare."

For Medicare Part C, see "Medicare Advantage".

Medicare Part B
Acronym: Part B

From the CMS web site: "Medicare Part B (Medical Insurance) - Part B helps cover doctors' services and outpatient care. It also covers some other medical services that Part A doesn't cover, such as some of the services of physical and occupational therapists, and some home health care. Part B helps pay for these covered services and supplies when they are medically necessary. Most people pay a monthly premium for Part B."

Medicare Part C
Acronym: Part C

The Medicare Part C program refers to Medicare managed care plans, also know as Medicare Advantage (MA). See "Medicare Advantage."

Medicare Part D
Acronym: Part D

From the CMS web site: "Medicare Part D (Prescription Drug Coverage) - Medicare prescription drug coverage is available to everyone with Medicare. To get Medicare prescription drug coverage, people must join a plan approved by Medicare that offers Medicare drug coverage. Most people pay a monthly premium for Part D."

Medicare Provider Analysis and Review
Acronym: MedPAR

From the ResDAC web site: "The MedPAR file contains information about inpatient (IP) hospital and skilled nursing facility (SNF) stays that were covered by Medicare.  Medpar records are created by rolling up information for a single stay from individual IP and SNF claims. "

Medicare Severity Diagnosis Related Group
Acronym: MS-DRG

From the CMS web site: "Section 1886(d) of the Act specifies that the Secretary shall establish a classification system (referred to as DRGs) for inpatient discharges and adjust payments under the IPPS (Inpatient Prospective Payment System) based on appropriate weighting factors assigned to each DRG." "Currently, cases are classified into Medicare Severity Diagnosis Related Groups (MS-DRGs) for payment under the IPPS based on the following information reported by the hospital: the principal diagnosis, up to 25 additional diagnoses, and up to 25 procedures performed during the stay."

Medicare Status Code
Acronym: MSC

From the ResDAC web site: "This variable indicates how a beneficiary currently qualifies for Medicare..." This variable occurs monthly.

Medicare-Medicaid Linked Enrollee Analytic Data Source
Acronym: MMLeads

From the CCW Medicare Data User Guide, "In 2013, CCW began to offer a new data product designed for studying the Medicare and Medicaid dually enrolled population. The data files are called the Medicare-Medicaid Linked Enrollee Analytic Data Source (MMLEADS). They are a suite of analytical files consisting of a combination of linkable beneficiary, service and clinical condition data files. The MMLEADS beneficiary-level and service-level data files are person-level files."

Medication Therapy Management
Acronym: MTM

From the CMS Prescription Drug Benefit Manual, Chaper 7, section 30.1 "A Part D sponsor must have established an MTMP that—Is designed to ensure that covered Part D drugs prescribed to targeted beneficiaries... are appropriately used to optimize therapeutic outcomes through improved medication use; Is designed to reduce the risk of adverse events, including adverse drug interactions, for targeted beneficiaries; May be furnished by a pharmacist or other qualified provider; and may distinguish between services in ambulatory and institutional settings."

Minimum Data Set
Acronym: MDS

From the CMS web site: "The Minimum Data Set (MDS) is part of the federally mandated process for clinical assessment of all residents in Medicare and Medicaid certified nursing homes.  This process provides a comprehensive assessment of each resident's functional capabilities and helps nursing home staff identify health problems."



National Claims History Repository
Acronym: NCHR

From the US department of Health and Human Services: "NCH contains billing and utilization information on Medicare beneficiaries enrolled in hospital insurance (Part A) or medical insurance (Part B) of the Medicare program."

National Death Index
Acronym: NDI

From the CDC web site: "The National Death Index (NDI) is a centralized database of death record information on file in state vital statistics offices.  Working with these ,state offices, the National Center for Health Statistics (NCHS) established the NDI as a resource to aid epidemiologists and other health and medical investigators with their mortality ascertainment activities."

National Drug Code
Acronym: NDC

From the FDA web site: "Drug products are identified and reported using a unique, three-segment number, called the National Drug Code (NDC), which serves as a universal product identifier for drugs."

National Provider Identifier
Acronym: NPI

From the CMS web site: "The National Provider Identifier (NPI) is a Health Insurance Portability and Accountability Act (HIPAA) Administrative Simplification Standard. The NPI is a unique identification number for covered health care providers. Covered health care providers and all health plans and health care clearinghouses must use the NPIs in the administrative and financial transactions adopted under HIPAA. The NPI is a 10-position, intelligence-free numeric identifier (10-digit number). This means that the numbers do not carry other information about healthcare providers, such as the state in which they live or their medical specialty. The NPI must be used in lieu of legacy provider identifiers in the HIPAA standards transactions."


National Claims History Repository 


National Drug Code

The FDA maintains a directory of drugs, each identified by a unique number called the National Drug Code or NDC. This serves as a universal product identifier for drugs, coding labeler, product, and trade package size.


National Death Index 


Not Otherwise Specified 

Not Otherwise Specified
Acronym: NOS

From the Centers for Disease Control guidelines for ICD-10 coding: "NOS “Not otherwise specified” This abbreviation is the equivalent of unspecified."


Nurse Practioner 


National Provider Identifier

Nurse Practitioner
Acronym: NP

From the National Cancer Institute: "A registered nurse who has additional education and training in how to diagnose and treat disease. Nurse practitioners are licensed at the state level and certified by national nursing organizations. In cancer care, a nurse practitioner may manage the primary care of patients and their families, based on a practice agreement with a doctor. Also called advanced practice nurse, APN, and NP. " 



Old Age, Survivors, and Disability Insurance


Old Age and Survivors Insurance 


Home Health Outcome and Assessment Information Set

Office of Management and Budget
Acronym: OMB

From the White House web site: "The Office of Management and Budget (OMB) serves the President of the United States in overseeing the implementation of his vision across the Executive Branch. Specifically, OMB’s mission is to assist the President in meeting his policy, budget, management and regulatory objectives and to fulfill the agency’s statutory responsibilities."

Office of the Inspector General
Acronym: OIG

From the US Department of Health and Human Services web site: "Office of Inspector General's (OIG) mission is to protect the integrity of Department of Health & Human Services (HHS) programs as well as the health and welfare of program beneficiaries." "HHS OIG is the largest inspector general's office in the Federal Government, with approximately 1,600 dedicated to combating fraud, waste and abuse and to improving the efficiency of HHS programs."


Office of the Inspector General 

Old Age and Survivors Insurance
Acronym: OASI

From the Social Security Administration web site, "The Old-Age and Survivors Insurance Trust Fund is a separate account in the United States Treasury. A fixed proportion (dependent on the allocation of tax rates by trust fund) of the taxes received under the Federal Insurance Contributions Act and the Self-Employment Contributions Act are deposited in the fund to the extent that such taxes are not needed immediately to pay expenses. Taxes are deposited in the fund on every business day."

Old Age, Survivors, and Disability Insurance
Acronym: OASDI

From the Social Security Administration, "The OASDI program—which for most Americans means Social Security—is the largest income-maintenance program in the United States. Based on social insurance principles, the program provides monthly benefits designed to replace, in part, the loss of income due to retirement, disability, or death. Coverage is nearly universal: About 96% of the jobs in the United States are covered.Workers finance the program through a payroll tax that is levied under the Federal Insurance and Self-Employment Contri-bution Acts (FICA and SECA)."


Office of Management and Budget 


Out-Of-Pocket Payment 


OOP (Out-Of-Pocket) Threshold




Outpatient Department 


Other Therapy or Other Services file 

Other Therapy or Other Services file
Acronym: OT
Out-Of-Pocket Payment
Acronym: OOP

From the web site: "...will count as out-of-pocket costs which will help you get out of the coverage gap. These items aren't counted toward your out-of-pocket spending: What the drug plan pays toward the drug cost (15% of the price in 2018); What the drug plan pays toward the dispensing fee (65% of the fee in 2018)" The referenced web site includes an example.

Out-Of-Pocket Threshold
Acronym: OOPT

From the CMS Prescription Drug Benefit Manual, Chapter 5, section 20.3.1: " – Defined standard coverage consists of coverage of covered Part D drugs subject to: An annual deductible: Twenty-five percent coinsurance for actual costs above the annual deductible but at or below an initial coverage limit; One hundred percent coinsurance for costs above the initial coverage limit and at or below the annual out-of-pocket threshold (also known as the coverage gap); Catastrophic coverage with nominal cost-sharing for the remainder of the coverage year once an enrollee’s costs exceed the annual out-of-pocket threshold."

Acronym: OP

From the Medicare Benefit Policy Manual, Chapter 6, Section 20.2: "A hospital outpatient is a person who has not been admitted by the hospital as an inpatient but is registered on the hospital records as an outpatient and receives services (rather than supplies alone) from the hospital or CAH."

Outpatient Department
Acronym: OPD

From the CMS web site for Outpatient Hospital, "A portion of a hospital which provides diagnostic, therapeutic (both surgical and nonsurgical), and rehabilitation services to sick or injured persons who do not require hospitalization or institutionalization. Part of the Hospital providing services covered by SMI, including services in an emergency room or outpatient clinic, ambulatory surgical procedures, medical supplies such as splints, laboratory tests billed by the hospital, etc. "



Physician Assistant


Program of All-Inclusive Care for the Elderly 


Prepaid Ambulatory Health Plan 

Part B
Part C
Part D
Part D Plan
Acronym: PDP

Stand-along Prescription Drug Plan; Medicare Part D Program benefit plan which is independent of any Medicare Advantage program.


Primary Care Case Management 


Prescription Drug Event 


Part D Plan

Stand-along Prescription Drug Plan; Medicare Part D Program benefit plan which is independent of any Medicare Advantage program.


Provider, Enrollment, Chain and Ownership System

CMS system for Medicare provider enrollment.
Some data from PECOS is publicly available.

People with Disease
Acronym: PWD
Per member per month
Acronym: PMPM

From the MACPAC web site:"States typically pay managed care organizations for risk-based managed care services through fixed periodic payments for a defined package of benefits. These capitation payments are typically made on a per member per month (PMPM) basis."

Peripheral Vascular Disease
Acronym: PVD

From the NIH National Heart, Lung, and Blood Institute web site: "Other names: Peripheral Artery Disease.: "

From the National Library of Medicine Medline Plus web site: "Peripheral arterial disease (PAD) happens when there is a narrowing of the blood vessels outside of your heart. The cause of PAD is atherosclerosis."

Personal Summary file
Acronym: PS

Private Fee-For-Service plan


Prepaid Health Plan 

Physician Assistant
Acronym: PA

From the CMS web site: "A person who has 2 or more years of advanced training and has passed a special exam. A physician assistant works with a doctor and can do some of the things a doctor does."


Prepaid Inpatient Health Plan


Provider Identification 


Per member per month 


Provider of Service 

Post-Traumatic Stress Disorder
Acronym: PTSD

From the National Library of Medicine, PubMed website: "Post-Traumatic Stress Disorder (PTSD): An anxiety disorder that develops in in response to one or more traumatic events such as deliberate acts of interpersonal violence, severe accidents, disasters or military action."


Preferred Provider Organization 


Prospective Payment System 

Preferred Provider Organization
Acronym: PPO

From the CMS Medicare Managed Care Manual, Chapter 1, section 20.2.2: "A PPO is a CCP (Coordinated Care Plan) plan that provides for reimbursement for all covered benefits regardless of whether the benefits are provided within the plan’s network of providers (42 CFR 422.4(a)(1)(v)(B); Section 1852(e)(3)(iv) of the Social Security Act). PPOs may be local or regional (42 CFR 422.4(a)(iii)(C))."

Prepaid Ambulatory Health Plan
Acronym: PAHP

From the web site: "Prepaid Ambulatory Health Plan (PAHP): Limited benefit package that does not include inpatient hospital or institutional services (examples: dental and transportation); Payment may be risk or non-risk."

Prepaid Health Plan
Acronym: PHP

From the CMS web site: "A prepaid managed care entity that provides less than comprehensive services on an at risk basis or one that provides any benefit package on a non-risk basis."

Prepaid Inpatient Health Plan
Acronym: PIHP

From the web site, "Prepaid Inpatient Health Plan (PIHP): Limited benefit package that includes inpatient hospital or institutional services (example: mental health); Payment may be risk or non-risk".

Prescription Drug
Acronym: RX

From the US Food and Drug Administration web site: "prescription"

Prescription Drug Event
Acronym: PDE

From the CMS web site: "Every time a beneficiary fills a prescription under Medicare Part D, a prescription drug plan sponsor must submit a summary record called the prescription drug event (PDE) data to CMS. The PDE data are not the same as individual drug claim transactions, but are summary extracts using CMS-defined standard fields."

Prescription Drug Plan
Acronym: PDP

From the Medicare Prescription Drug Benefit Manual, Chapter 1, section 20, "Prescription drug plan or PDP: Prescription drug coverage that is offered under a policy, contract, or plan that has been approved as specified in 42 CFR 423.272 and that is offered by a PDP sponsor that has a contract with CMS that meets the contract requirements under subpart K of 42 CFR 423."

Primary Care Case Management
Acronym: PCCM

From the web site: "Primary Care Case Management (PCCM): Primary care case managers contract with the state to furnish case management (location, coordination, and monitoring) services; Generally, paid fee-for-service for medical services rendered plus a monthly case management fee."

Private Fee-For-Service plan
Acronym: PFFS

From the CMS web site: "A Private Fee-For-Service (PFFS) plan is a Medicare Advantage (MA) health plan, offered by a State licensed risk bearing entity, which has a yearly contract with the Centers for Medicare & Medicaid Services (CMS) to provide beneficiaries with all their Medicare benefits, plus any additional benefits the company decides to provide. The PFFS plan: Pays providers on a fee-for-service basis without placing the providers at financial risk; Varies provider payment rates only based on the specialty or location of the provider or to increase utilization of certain preventive or screening services; Does not restrict members' choices among providers that are lawfully authorized to furnish services and accept the plan's terms and conditions of payment; and Does not permit the use of prior authorization or notification."

Program of All-Inclusive Care for the Elderly
Acronym: PACE

From the CMS web site: "PACE combines medical, social, and long-term care services for frail people. PACE is available only in states that have chosen to offer it under Medicaid. To be eligible, you must: Be 55 years old, or older, Live in the service area of the PACE program, Be certified as eligible for nursing home care by the appropriate state agency , and Be able to live safely in the community. The goal of PACE is to help people stay independent and live in their community as long as possible, while getting high quality care they need."

Prospective Payment System
Acronym: PPS

From the CMS web site: " Prospective Payment System (PPS) is a method of reimbursement in which Medicare payment is made based on a predetermined, fixed amount. The payment amount for a particular service is derived based on the classification system of that service (for example, diagnosis-related groups for inpatient hospital services).  CMS uses separate PPSs for reimbursement to acute inpatient hospitals, home health agencies, hospice, hospital outpatient, inpatient psychiatric facilities, inpatient rehabilitation facilities, long-term care hospitals, and skilled nursing facilities."

Prostate Specific Antigen
Acronym: PSA

From the web site: "A prostate-specific antigen (PSA) test is a test that measures the level of PSA in the blood. PSA is a substance made mostly by the prostate that may be found in an increased amount in the blood of men who have prostate cancer. The level of PSA may also be high in men who have an infection or inflammation of the prostate or benign prostatic hyperplasia (BPH; an enlarged, but noncancerous, prostate)."

Provider Enrollment, Chain and Ownership System
Acronym: PECOS

From the CMS web site: "CMS has established Internet-based Provider Enrollment, Chain and Ownership System (PECOS) as an alternative to the paper (CMS-855) enrollment process. Internet-based PECOS will allow physicians, non-physician practitioners and provider and supplier organizations to enroll, make a change in their Medicare enrollment, view their Medicare enrollment information on file with Medicare, or check on status of a Medicare enrollment application via the Internet. "

Provider Identification Number
Acronym: PIN

From the ResDAC web site: "The identification number of the institutional provider certified by Medicare to provide services to the beneficiary. NOTE: Effective October 1, 2007 the OSCAR Provider Number has been renamed the CMS Certification Number (CCN). The name was changed to avoid confusion with the National Provider Identifier (NPI). The CCN (OSCAR Provider Number) will continue to play a critical role in verifying that a provider has been Medicare certified and for what type of services."

Provider of Service
Acronym: POS

From the CMS web site: "The POS (Provider of Services) file contains data on characteristics of hospitals and other types of healthcare facilities, including the name and address of the facility and the type of Medicare services the facility provides, among other information.  The data are collected through the Centers for Medicare & Medicaid Services (CMS) Regional Offices. The file contains an individual record for each Medicare-approved provider and is updated quarterly."


Personal Summary file 


Prostate Specific Antigen (screening test for prostate cancer)


Post-Traumatic Stress Disorder

Public Use File
Acronym: PUF

From the CMS web site: "The Centers for Medicare & Medicaid Services (CMS) makes certain Non-Identifiable Data Files (also known as public use files or PUFs) available for order. Non-Identifiable Data Files do not contain any protected health information (PHI) or personally identifiable information (PII). As a result, CMS has not set any restrictions on who may purchase these files and does not require requestors to sign a Data Use Agreement."


Public Use File 


Peripheral Vascular Disease


People with Disease 



Quality Assurance Surveillance Plan


Qualified Disabled and Working Individuals


Qualified Individual 


Qualified Medicare Beneficiary 

Qualified Disabled and Working Individuals
Acronym: QDWI

From the CMS web site: "Qualified Disabled and Working Individuals (QDWIs) - These individuals lost their Medicare Part A benefits due to their return to work. They are eligible to purchase Medicare Part A benefits, have income of 200% FPL or less and resources that do not exceed twice the limit for SSI eligibility, and are not otherwise eligible for Medicaid. Medicaid pays the Medicare Part A premiums only. FFP equals FMAP."

Qualified Medicare Beneficiary
Acronym: QMB

From the CMS web site: "Qualified Medicare Beneficiaries (QMBs) without other Medicaid (QMB Only) - These individuals are entitled to Medicare Part A, have income of 100% Federal poverty level (FPL) or less and resources that do not exceed twice the limit for SSI eligibility, and are not otherwise eligible for full Medicaid." "QMBs with full Medicaid (QMB Plus) - These individuals are entitled to Medicare Part A, have income of 100% FPL or less and resources that do not exceed twice the limit for SSI eligibility, and are eligible for full Medicaid benefits."

Qualified Working and Disabled Individual
Acronym: QWDI
Qualified Working Individual
Acronym: QWI
Quality Assurance Surveillance Plan
Acronym: QASP

From the CMS web site: "The Centers for Medicare & Medicaid Services (CMS) has compiled a summary of overall Medicare Administrative Contractor (MAC) performance information as measured by the Quality Assurance Surveillance Plan (QASP) and Award Fee Plan (AF).  The QASP ensures that systematic quality assurance methods are used in administration of the contract and provides Government Surveillance oversight on the quality, quantity, and timeliness of contractor performance."


Qualified Working and Disabled Individual


Railroad Retirement Board
Acronym: RRB

From the US Railroad Retirement Board web site: "The Railroad Retirement Board (RRB) is an independent agency in the executive branch of the Federal Government. The RRB’s primary function is to administer comprehensive retirement-survivor and unemployment-sickness benefit programs for the nation’s railroad workers and their families, under the Railroad Retirement and Railroad Unemployment Insurance Acts. As part of the retirement program, the RRB also has administrative responsibilities under the Social Security Act for certain benefit payments and railroad workers’ Medicare coverage."


Research Data Distribution Center Original contractor until 12-31-08 Acumen, LLC


From the CMS web site: "Each year CMS reassigns low income beneficiaries from PDPs that are going above the regional LIS benchmark (and did not, or could, not waive a de minimis amount of premium above the benchmark), and from PDPs and MA plans that are terminating (which includes MA plans that are reducing their service areas).  These beneficiaries are reassigned into a PDP that is below the regional LIS benchmark."

Relative Value Units
Acronym: RVU

From the CMS web site: "The Medicare physician fee schedule pricing amounts are adjusted to reflect the variation in practice costs from area to area. A geographic practice cost index (GPCI) has been established for every Medicare payment locality for each of the three components of a procedure's relative value unit (i.e., the RVUs for work, practice expense, and malpractice). The GPCIs are applied in the calculation of a fee schedule payment amount by multiplying the RVU for each component times the GPCI for that component."


Research Data Assistance Center 

Research Data Assistance Center
Acronym: ResDAC

From the ResDAC web site: "Established in 1996, the Research Data Assistance Center (ResDAC) is a Centers for Medicare and Medicaid Services (CMS) contractor that provides free assistance to researchers interested in the CMS data. As a CMS contractor, we provide assistance to academic, non-profit, for-profit and government researchers."

Research Data Distribution Center
Acronym: RDDC

From the CMS web site: "The Research Data Distribution Center (RDDC) disseminates Medicare and Medicaid data to public and private researchers." "Once the period of performance for these two contracts has ended, the plan is to solicit a new contract to combine the Medicare and Medicaid data dissemination activities of the RDDC and the CCW into a single contract with a single database." "End date 12-16-2010"

Research Identifiable File
Acronym: RIF

From the CMS web site: "The Centers for Medicare & Medicaid Services (CMS) makes identifiable data files (IDFs) available to certain stakeholders as allowed by federal laws and regulations as well as CMS policy. IDFs contain protected health information (PHI) and/or personally identifiable information (PII) and CMS is committed to ensuring this information is protected. CMS allows organizations to access IDFs, also known as research identifiable files (RIFs), for research purposes."

Resource Utilization Group
Acronym: RUG

From the CMS website: "Section 4432(a) of the Balanced Budget Act (BBA) of 1997 modified how payment is made for Medicare skilled nursing facility (SNF) services. Effective with cost reporting periods beginning on or after July 1, 1998, SNFs are no longer paid on a reasonable cost basis or through low volume prospectively determined rates, but rather on the basis of a prospective payment system (PPS)." "Per diem payments for each admission are case-mix adjusted using a resident classification system (Resource Utilization Groups, version IV (RUG-IV)) based on data from resident assessments (MDS 3.0) and relative weights developed from staff time data."


Research Identifiable File


Railroad Retirement Board 


Relative Value Units


Prescription Drug



Standard Analytical Files 


Substance Abuse and Mental Health Services Administration


Statistical Analysis Software 


State Children's Health Insurance Program


Surveillance, Epidemiology and End Results cancer registries


Social HMO (Health Maintenance Organization) 

Skilled Nursing Facility
Acronym: SNF

From the web site: "Skilled care is health care given when you need skilled nursing or therapy staff to treat, manage, observe, and evaluate your care. Examples of SNF care include intravenous injections and physical therapy." "Skilled care involves safe and effective care given by skilled nursing or rehabilitative staff."


Specified Low-income Medicare Beneficiary 


State Medicaid Research Files

Social Health Maintenance Organization
Acronym: SHMO

From the CMS web site: "This demonstration project was implemented to test the concept of a social health maintenance organization (S/HMO) for acute and long-term care. An S/HMO integrates health and social services under the direct financial management of the provider of services. All services were provided by or through the S/HMO at a fixed, annual, prepaid capitation sum."

Social Security Administration
Acronym: SSA

From the website: "The Social Security Administration assigns Social Security numbers, and administers the Social Security retirement, survivors, and disability insurance programs. They also administer the Supplemental Security Income program for the aged, blind, and disabled."

Social Security Disability Insurance
Acronym: SSDI

From the web site: "Social Security Disability Insurance pays benefits to you and certain members of your family if you are "insured," meaning that you worked long enough and paid Social Security taxes."

Social Security Number
Acronym: SSN

From the Social Security Administration web site: "The use of the Social Security number (SSN) has expanded significantly since its inception in 1936. Created merely to keep track of the earnings history of U.S. workers for Social Security entitlement and benefit computation purposes, it has come to be used as a nearly universal identifier. Assigned at birth, the SSN enables government agencies to identify individuals in their records and businesses to track an individual's financial information. "

Special Needs Plan
Acronym: SNP

From the CMS web site: "A special needs plan (SNP) is a Medicare Advantage (MA) coordinated care plan (CCP) specifically designed to provide targeted care and limit enrollment to special needs individuals."

Specified Low-income Medicare Beneficiary
Acronym: SLMB

From the CMS web site: "Specified Low-Income Medicare Beneficiaries (SLMBs) without other Medicaid (SLMB Only) - These individuals are entitled to Medicare Part A, have income of greater than 100% FPL, but less than 120% FPL and resources that do not exceed twice the limit for SSI eligibility, and are not otherwise eligible for Medicaid." "SLMBs with full Medicaid (SLMB Plus) - These individuals are entitled to Medicare Part A, have income of greater than 100% FPL, but less than 120% FPL and resources that do not in exceed twice the limit for SSI eligibility, and are eligible for full Medicaid benefits. Medicaid pays their Medicare Part B premiums and provides full Medicaid benefits."


Social Security Administration


Social Security Disability Insurance 


Supplemental Security Income 


Social Security Number 

Standard Analytical Files
Acronym: SAF

From the CMS web site: "LDS Standard Analytic Files (SAFs), also known as Medicare claims files, are available for each claim type (Inpatient, Outpatient, Skilled Nursing Facility, Home Health Agency, Hospice, Carrier and Durable Medical Equipment)."

State Children's Health Insurance Program
Acronym: SCHIP

From the website: "The State Children’s Health Insurance Program (now referred to as CHIP, not SCHIP) was enacted with bipartisan support a decade ago as part of the Balanced Budget Act of 1997 (BBA). Together with Medicaid, CHIP has helped to reduce the rate of low-income uninsured children by expanding eligibility levels and simplifying enrollment procedures."

State Medicaid Research Files
Acronym: SMRF

From the CMS web site: "CMS began producing State Medicaid Research File (SMRF) data from MSIS in the late 1980s for a small group of participating states.  The number of states for which SMRF were produced increased greatly in 1992 and continued to increase through 1998 as participation in MSIS grew.  The Balanced Budget Act (BBA) of 1997 mandated that all states report MSIS data beginning in 1999.  Along with the BBA mandate, data collection in MSIS expanded and SMRF was given a new name – MAX.  SMRF data are not available for requests."

Statistical Analysis Software
Acronym: SAS

From the SAS web site: "SAS is an integrated system of software solutions that enables you to perform the following tasks: data entry, retrieval, and management; report writing and graphics design; statistical and mathematical analysis; business forecasting and decision support; operations research and project management; applications development. Some people use many of the capabilities of the SAS System, and others use only a few."

Statististical Package for the Social Sciences
Acronym: SPSS

From the IBM web site: "The IBM SPSS® software platform offers advanced statistical analysis, a vast library of machine-learning algorithms, text analysis, open-source extensibility, integration with big data and seamless deployment into applications."

Step Therapy

From the CMS web site: "One form of prior authorization is step therapy. With step therapy, in most cases, you must first try certain less expensive drugs that have been proven effective for most people with your condition."

Substance Abuse and Mental Health Services Administration
Acronym: SAMHSA

From the agency web site: "The Substance Abuse and Mental Health Services Administration (SAMHSA) is the agency within the U.S. Department of Health and Human Services that leads public health efforts to advance the behavioral health of the nation. SAMHSA's mission is to reduce the impact of substance abuse and mental illness on America's communities."

Supplemental Security Income
Acronym: SSI

From the web site: "Supplemental Security Income (SSI) is a Federal income supplement program funded by general tax revenues (not Social Security taxes): It is designed to help aged, blind, and disabled people, who have little or no income; and It provides cash to meet basic needs for food, clothing, and shelter."

Surveillance, Epidemiology and End Results cancer registries
Acronym: SEER

From the NIH National Cancer Institute web site: "The Surveillance, Epidemiology, and End Results (SEER) Program provides information on cancer statistics in an effort to reduce the cancer burden among the U.S. population."



Transformed Medicaid Statistical Information System


Temporary Assistance for Needy Families 

Temporary Assistance for Needy Families
Acronym: TANF

From HHS Office of Administration for Children and Families: "The Temporary Assistance for Needy Families (TANF) program is designed to help needy families achieve self-sufficiency. States receive block grants to design and operate programs that accomplish one of the purposes of the TANF program."


Total Hip Replacement 


From the web site: "Each Medicare drug plan has its own list of covered drugs (called a formulary). Many Medicare drug plans place drugs into different "tiers" on their formularies. Drugs in each tier have a different cost. A drug in a lower tier will generally cost you less than a drug in a higher tier."


Total Knee Replacement 


Type of Service 

Total Hip Replacement
Acronym: THR

From US National Library of Medicine, Medline Plus: "Hip replacement is surgery for people with severe hip damage. The most common cause of damage is osteoarthritis. Osteoarthritis causes pain, swelling, and reduced motion in your joints."

Total Knee Replacement
Acronym: TKR

From the US National Library of Medicine, Medline Plus: "Knee replacement is surgery for people with severe knee damage. Knee replacement can relieve pain and allow you to be more active. Your doctor may recommend it if you have knee pain and medicine and other treatments are not helping you anymore. When you have a total knee replacement, the surgeon removes damaged cartilage and bone from the surface of your knee joint and replaces them with a man-made surface of metal and plastic."

Transformed Medicaid Statistical Information System
Acronym: T-MSIS

From the web site: "The Transformed Medicaid Statistical Information System (T-MSIS) is a critical data and systems component of the CMS Medicaid and CHIP Business Information Solution (MACBIS)." "The Medicaid and Statistical Information System (MSIS) used by the Centers for Medicare and Medicaid Services (CMS) to gather key eligibility, enrollment, program, utilization and expenditure data for the Medicaid and Children's Health Insurance Program (CHIP) has been decommissioned and replaced by T-MSIS."


True Out of Pocket Costs

True Out of Pocket Costs
Acronym: TrOOP

From the Medicare Prescription Drug Benefit Manual, Chapter 5, section 30: "Not all enrollee out-of-pocket expenditures are considered incurred (or “true-out-of-pocket,” or TrOOP, expenditures) for purposes of applicability toward beneficiary spending against the annual out-of-pocket threshold described in section 20.3.1. Sections 30.1 and 30.2 provide further detail on whether certain expenditures are TrOOP-eligible or not, and Table 3 provides a summary of those discussions."

Type of Service
Acronym: TOS

From the Medicaid Analytic Extract data dictionary: "Code indicating the Medicaid Analytic Extracts (MAX) type of service for this record"



Earlier version of the UB-04. See CMS form 1450.

Unique Physician Identification Number
Acronym: UPIN

From the CMS web site: "The Unique Physician Identification Number (UPIN) Directory contains selected information on physicians, doctors of Osteopathy, limited licensed practitioners and some non physician practitioners who are enrolled in the Medicare Program." "Beginning with the 4th Quarter 2006 update, the existing records in the UPIN file will no longer be updated. New records will continue to be added through 2nd Quarter 2007, after which the UPIN file will be discontinued. The National Provider Identifier (NPI) is replacing the UPIN as the CMS provider identification number."

United States Food and Drug Administration
Acronym: FDA

From the FDA website: "The Food and Drug Administration (FDA) is an agency within the U.S. Department of Health and Human Services." and "FDA is responsible for:
    Protecting the public health by assuring that foods (except for meat from livestock, poultry and some egg products which are regulated by the U.S. Department of Agriculture) are safe, wholesome, sanitary and properly labeled; ensuring that human and veterinary drugs, and vaccines and other biological products and medical devices intended for human use are safe and effective
    Protecting the public from electronic product radiation
    Assuring cosmetics and dietary supplements are safe and properly labeled
    Regulating tobacco products
    Advancing the public health by helping to speed product innovations"


Unique Physician Identification Number


Virtual Research Data Center
Acronym: VRDC

From the CCW web site: "What is the CMS VRDC? (FAQ006) A: The CMS VRDC is an alternative solution for accessing and analyzing CMS data for research purposes. Historically, CMS has provided data to researchers by preparing and shipping encrypted data files on external media. The VRDC allows researchers to access and perform their own analysis and manipulation of CMS data virtually from their own workstation. The VRDC provides researchers with a secure mechanism to access timelier data in a more efficient and cost-effective manner."


Virtual Research Data Center 


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