Home  /   Data Sources  /   Rehabilitation Dataset Directory: Search  /   Dataset Profile Center for Large Data Research & Data Sharing in Rehabilitation

Rehabilitation Dataset Directory: Dataset Profile

Dataset: Outcome and Assessment Information Set (OASIS)

Basic Information
Dataset Full Name Outcome and Assessment Information Set
Dataset Acronym OASIS

The Outcome and Assessment Information Set (OASIS) is a patient specific, comprehensive assessment tool/database designed to measure the quality of home health services and patient health outcomes. OASIS contains data on all adult (ages 18 years and older) Medicare and Medicaid patients who receive non-maternity skilled health services from Medicare certified home health care agencies. It is completed by home health care personnel (typically an RN) and is specifically designed to measure changes in patient health status between two or more time periods.

OASIS is longitudinal including the patient’s health profile at the beginning of services, with follow-up(s) every 60 days during receipt of services, and at discharge. It includes measures of services utilization, quality improvements, and patient-level risk factors for adverse health outcomes among other topics. The OASIS data contains patient case mix profile reports and patient outcome reports which are used for reimbursement purposes and certification process.

In 2010, a comprehensive version of OASIS (OASIS-C) was implemented to add more information on process of care and clinical interventions. OASIS-C2 is the current version, which accounts for recent changes within the health care system (e.g., to evaluate home health care quality).

Key Terms Skilled care, Home Health Agency, Home Health services, Medicare, Medicaid, Quality of care, Therapy
Study Design Longitudinal
Data Type(s) Administrative
Sponsoring Agency/Entity

Department of Health and Human Services (HHS)

Centers for Medicare and Medicaid Services (CMS)

Health Conditions/Disability Measures
Health Condition(s)

Alzheimer's/dementia, Anxiety disorders, Body mass index (BMI)/obesity, Cardiovascular conditions, Chronic pain, Depression, Diabetes, Heart attack, ICD-9/10 diagnostic codes, Pulmonary disorders, Stroke

Disability Measures Ambulatory disability, Cognitive disability, Communication impairment, Functional limitations (ADLs and/or IADLs), Hearing disability, Independent living disability, Mental health disability, Self-care disability, Special equipment use/assistive technology, Visual disability
Measures/Outcomes of Interest
Topics Socio-demographic, Environmental/living arrangements, Health status, Health service utilization, Medication management, Equipment use, Therapy need, Number of visits, Plan of care/intervention, Functional status (ADL/IADL, ambulation, transfer, dressing, assistance from caregiver, cognitive functioning), Fall risk assessment, Fall prevention, Wound and pressure ulcer management, Urinary incontinence/urinary tract infection, Pain/pain management, Obesity, Unplanned hospital admissions, Emergent care, Inpatient facility admission, Discharge disposition, Hospital admission reason, Nursing home admission reason
Sample Population Adult (ages 18 years and older) Medicare and Medicaid patients (non-maternity) who receive skilled health services from a licensed Home Health Agency (HHA)
Sample Size/Notes

Adult (ages 18 years and older) non-maternity Medicare and Medicaid patients receiving skilled health services from certified Home Health Agency.

  • 2010: 10,800 Medicare certified home health agencies 
  • 2010: 3,446,057 beneficiaries were served
  • 2010: 122,578,603 visits made
Unit of Observation Individual
Continent(s) North America

United States

Geographic Coverage United States
Geographic Specificity State and Zip Code
Special Population(s)

Medicare and Medicaid patients (who receive non-maternity skilled health services from Medicare certified home health care agencies)

Data Collection
Data Collection Mode Combination of In-person patient observation and interview
Years Collected 1999-present
Data Collection Frequency Start of care; Resumption of care following inpatient facility stay; Recertification within the last five days of each 60-day recertification period; Other follow-up during the home health episode of care; Transfer to inpatient facility; Discharge from home care; Death at home
Strengths and Limitations
Strengths Large sample size, both clinical and functional status data. Includes home health care services such as nursing care, physical therapy, occupational therapy, speech-language therapy, and medical-social services. OASIS data can be linked with claims and/or other CMS non-CMS data.
Limitations Does not include vital sign data or home health care reimbursed by payers other than Medicare/Medicaid.
Data Details
Primary Website https://www.cms.gov/Medicare/Quality-Initiatives-Patient-Assessment-Instruments/HomeHealthQualityInits/OASIS-Data-Sets
Data Access Home Health Outcome and Assessment Information Set is available from RESDAC: https://www.resdac.org/cms-data/request/research-identifiable-files
Data Access Requirements Data Use agreement, No cost
Summary Tables/Reports Home Health Compare Database:
Data Components NA
Selected Papers
Other Papers

Medicare Payment Advisory Commission (MedPAC), Chapter 9: Home health care services, in Report to the Congress: Medicare payment policy, Medicare Payment Advisory Commission (MedPAC), Editor. March 2013, MedPAC: Washington DC. Pages 186-212. http://www.medpac.gov/docs/default-source/reports/mar17_entirereport.pdf

Tullai-McGuinness, Susan, Madigan, Elizabeth, Fortinsky, Richard (2009). “Validity Testing the Outcomes and Assessment Information Set (OASIS).” Home Health Care Serv Q.; 28(1): 45–57. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3070156/pdf/nihms-282994.pdf


OASIS User Manuals:


OASIS Data Documentation:


Researchers requesting OASIS assessment data for beneficiaries using Home Health services must select and justify each variable needed for their study.

OASIS Variable Justification Worksheet:


Related Repositories

Ask Our Researchers

Have a question about disability data or datasets?
E-mail your question to our researchers at disabilitystatistics@cornell.edu

The Rehabilitation Research Cross-dataset Variable Catalog has been developed through the Center for Large Data Research & Data Sharing in Rehabilitation (CLDR). The Center for Large Data Research and Data Sharing in Rehabilitation involves a consortium of investigators from the University of Texas Medical Branch, Cornell University's Yang Tan Institute (YTI), and the University of Michigan. The CLDR is funded by NIH - National Institute of Child Health and Human Development, through the National Center for Medical Rehabilitation Research, the National Institute for Neurological Disorders and Stroke, and the National Institute of Biomedical Imaging and Bioengineering. (P2CHD065702).

Other CLDR supported resources and collaborative opportunities:

Acknowledgements: This tool was developed through the efforts of William Erickson and Arun Karpur, and web designers Jason Criss and Jeff Trondsen at Cornell University. Many thanks to graduate students Kyoung Jo Oh and Yeong Joon Yoon who developed much of the content used in this tool.

For questions or comments please contact disabilitystatistics@cornell.edu