The HOS program is used by the Centers for Medicare & Medicaid Services (CMS) to gather data on the quality of care provided by Medicare Advantage Organizations (MAOs).

: You may see it alongside other coded fields like F18PBPID (Plan Benefit Package ID) or STATE in the HOS Data User’s Guide .

It is not a consumer file compression software like WinZip or 7-Zip. Instead, it refers to the associated with specific research "Cohorts." Technical Definition

If you were looking for an archive tool, you might be thinking of the , which is a popular app for opening ZIP and RAR files.