OASIS Glossary

TL;DR

OASIS picks up a lot of shorthand. CMS-speak, billing-speak, and clinical-speak all collide on the same form, and a clinician new to home health is trying to keep track of three vocabularies at once. This page is the cheat sheet — short definitions for the abbreviations that show up on the rest of this manual.

Terms

• BIMS — Brief Interview for Mental Status. A short cognitive screen used in OASIS Section C to assess attention, recall, and orientation. Triggers further cognitive items based on the score.
• CASPER — Certification and Survey Provider Enhanced Reports. The CMS reporting system where agencies pull final OASIS validation status, lateness flags, dash usage rates, and quality measure performance. Run alongside iQIES.
• CMS — Centers for Medicare & Medicaid Services. The federal agency that defines OASIS, sets payment rules (HH PPS, PDGM), and runs the surveys that pull your charts.
• CoP — Conditions of Participation. The federal regulations at 42 CFR 484 that home health agencies must meet to be Medicare-certified. The comprehensive assessment requirement (484.55) lives here.
• dash response (—) — The "not assessed" entry on an OASIS item. Different from NA. Used as a last resort when assessment was attempted but not obtainable. Tracked at the agency level on CASPER.
• Discharge — The OASIS timepoint at the end of a patient's home health episode for any reason other than transfer or death. RFA 09. Drives outcome quality measures.
• GG items — The Section GG self-care and mobility items, scored on a 6-point scale (06 Independent through 01 Dependent) plus four "activity not attempted" codes. Used at SOC/ROC and Discharge for outcome measurement.
• HARP — Healthcare Quality Information System Access Roles and Profiles. The CMS authentication system used to access iQIES and CASPER. Each agency needs HARP-credentialed users with the right roles.
• HH — Home Health. The Medicare benefit category covered under 42 CFR 484 and reimbursed via HH PPS.
• HHA — Home Health Agency. A Medicare-certified provider that delivers skilled home health services.
• HHCAHPS — Home Health Consumer Assessment of Healthcare Providers and Systems. The patient experience survey whose results feed into the public Care Compare ratings.
• HH PPS — Home Health Prospective Payment System. The CMS payment framework for home health, currently driven by PDGM groupings calculated from OASIS and claim data.
• HH-VBP — Home Health Value-Based Purchasing. The CMS performance program that adjusts agency payment based on quality measure performance, including OASIS-derived measures.
• HHRG — Home Health Resource Group. The case-mix grouping used under the legacy episode-based payment system. Replaced by PDGM in 2020 and is no longer used for payment, but still appears in older documentation.
• HIPPS — Health Insurance Prospective Payment System code. The 5-character code on home health claims that encodes the PDGM grouping for billing.
• iQIES — Internet Quality Improvement and Evaluation System. The CMS portal where agencies submit OASIS records and pull CASPER reports. Replaced QIES ASAP in January 2020. Authenticated via HARP.
• M0090 — Date Assessment Completed. The single most consequential date on an OASIS — anchors completion-window checks, the 30-day transmission clock, and the audit trail.
• M0100 — Reason for Assessment (RFA). The OASIS item that identifies the type of assessment (SOC, ROC, Recert, Transfer, Discharge, etc.). Drives which items must be completed and how the record is processed.
• NA — Not Applicable. The valid response on an OASIS item when the question doesn't apply to the patient's situation. Different from a dash and different from a skipped item.
• NOA — Notice of Admission. The 5-day initial billing notification under PDGM that tells the Medicare contractor a home health episode has started. Replaced the legacy RAP in 2022.
• OASIS — Outcome and Assessment Information Set. The CMS-mandated comprehensive assessment data set used in home health to drive payment, quality measurement, and care planning.
• OASIS-E2 — The current OASIS version. Builds on OASIS-E with additional standardized items aligned across post-acute settings.
• OBQI — Outcome-Based Quality Improvement. The legacy CMS framework for using OASIS outcome data to drive agency quality improvement. Largely subsumed by current quality measure programs.
• OBQM — Outcome-Based Quality Monitoring. The legacy companion to OBQI focused on adverse event monitoring. Most active reporting has moved to CASPER quality measures.
• PBQI — Process-Based Quality Improvement. The process-measure complement to OBQI in the older OASIS quality framework. Mostly historical at this point.
• PDGM — Patient-Driven Groupings Model. The current home health payment model, effective January 2020. Uses OASIS items, principal diagnosis, comorbidities, admission source, and timing to assign each 30-day period to one of 432 case-mix groups.
• PHQ-2 / PHQ-9 — Patient Health Questionnaire (2-item screen and 9-item full instrument). Section D depression screen on OASIS. PHQ-2 acts as the gateway; if positive, PHQ-9 is administered.
• QIES ASAP — Quality Improvement Evaluation System Assessment Submission and Processing. The legacy CMS submission system for OASIS, retired in January 2020. Replaced by iQIES.
• QM — Quality Measure. CMS-defined metrics calculated from OASIS, claims, and HHCAHPS data, published on Care Compare and used in HH-VBP scoring.
• RAP — Request for Anticipated Payment. The legacy initial billing under HH PPS. Eliminated in 2022 and replaced by the NOA. Still appears in older training materials.
• Recert — Recertification. The OASIS timepoint completed in the last 5 days of a 60-day cert when the patient continues home health services. RFA 04.
• RFA — Reason for Assessment. The M0100 value identifying the type of OASIS being submitted. See the RFA Codes page for the full list.
• ROC — Resumption of Care. The OASIS timepoint required when a patient returns to the agency after a 24+ hour inpatient stay during an active cert. RFA 03. Has a 2-day completion window.
• SOC — Start of Care. The OASIS timepoint at home health admission. RFA 01. Anchors the 60-day cert period and has a 5-day completion window.
• Transfer — The OASIS timepoint when a patient is admitted to an inpatient facility for 24+ hours during an active cert. RFA 06 if the agency keeps the patient on census, RFA 07 if the agency simultaneously discharges.

Related

• RFA Codes (01–09) — full breakdown of each RFA value
• OASIS Assessment Schedule — SOC, ROC, Recert, Discharge explained