**Certificate for OASIS Specialist–Clinical (COS-C)** is a professional credential for individuals who demonstrate advanced knowledge of the Outcome and Assessment Information Set (OASIS) and its accurate application according to current **CMS guidance**. Designed for **home health clinicians, OASIS educators, QAPI reviewers, clinical managers, consultants,** and other professionals involved in OASIS assessment, review, education, or oversight, the COS-C validates knowledge that goes beyond basic familiarity. The **2.5-hour COS-C Exam** evaluates knowledge and clinical judgment related to **OASIS regulations, data collection time points, applicable patient populations, data collection conventions,** and **item-by-item application of CMS guidance**. Earning the designation reflects a commitment to **assessment accuracy, sound decision-making, regulatory compliance, appropriate reimbursement,** and **reliable quality outcomes**.