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Outcome and Assessment Information Set (OASIS)

The Outcome and Assessment Information Set (OASIS) is a group of standard data elements developed, tested and refined over the past two decades through an extensive research and demonstration program funded largely by the Centers for Medicare and Medicaid Services (CMS), the Robert Wood Johnson Foundation and the New York State Department of Health. The OASIS data elements are designed to enable systematic comparative measurement of home health care patient outcomes at two points in time in adult skilled Medicare and Medicaid, non-maternity home health care patients.  Outcome measures are the basis for outcome-based quality improvement (OBQI) efforts that home health agencies (HHAs) can employ to assess and improve the quality of care they provide to patients.  An example of an OASIS-based outcome measure is whether a patient improves in the ability to ambulate between home health start of care and discharge, with ambulation ability measured according to a precise zero-to-five scale (as indicated by the OASIS ambulation item).

A new version of OASIS, OASIS-C, was implemented in January, 2010.  It represents the most comprehensive revision to OASIS since its original release in 1999.  OASIS-C items were created to increase clarity in measurement, replace items being eliminated from the previous version of OASIS,

and measure processes of care through the use of assessment tools (included in a comprehensive assessment) or the planning and delivery of specific clinical interventions.


The OASIS was not intended to be a comprehensive assessment instrument.  Instead, OASIS data items are collected at start of care, 60-day follow-ups and discharge (and surrounding an inpatient-facility stay) and are incorporated into a comprehensive patient assessment.  Home health agencies (HHAs) will find it necessary to supplement the OASIS items in order to comprehensively assess the health status and care needs of patients. For example, the OASIS does not include vital signs which are a common part of a patient assessment.


OASIS patient assessment data collected by the HHAs and submitted to the State of Ohio at the specific time points listed above in accordance with federal regulations serve to meet the quality reporting requirements necessary for CMS to administer HHA payment rate methodologies.  HHA’s

that do not comply with the OASIS reporting requirements are liable for a reduction in their reimbursement rate.  Additionally, some of the OASIS items submitted to the state will be reflected on the Home Health Compare website.  Home Health Compare can be used to review the performance of agencies in a specific area, help HHAs identify opportunities for quality improvement, as well as answer patient’s questions and educate them about their choices. 


Mailing Address:
Ohio Department of Health
Office of Health Assurance and Licensing, OASIS
246 North High Street
Columbus, OH 43215

Telephone: (614) 466-0190
Fax: (614) 564-2459


Last Updated: 06/13/2018