OPERA is a software tool that analyzes home health OASIS data patterns to identify potential errors and inconsistencies before agencies submit data to CMS. It contains over 20,000 analytics models to flag issues for clinicians to review and make decisions about patient care. OPERA helps agencies achieve the lowest possible Avoidable Adverse Determination rates by clarifying documentation and ensuring accurate OASIS assessments. It also tracks changes between assessments and provides guidance on common regulatory, recertification, and ZPIC post-payment audit edits. The document encourages users to utilize OPERA's consulting services for assistance in reducing Avoidable Adverse Determination frequencies.