Under the resource-based relative value scale (RBRVS) of the Medicare fee schedule, the weighted sum of the Geographic Practice Cost Indices (GPCI) for each geographic area. Also see geographic practice cost indices (GPCIs) .

In the Medicare program, this is a system used to convert the Medicare average United States fee-for-service per capita costs (USPCCs) to the local adjusted average per capita costs (AAPCCs). This is used to pay Medicare risk contracting health maintenance organizations (HMOs).

One of three components of the system in the Medicare program that is used in bringing fees for professional services in line for the region where each physician practices. It is pronounced “gypsies.” Under the resource-based relative value scale (RBRVS) of the Medicare fee schedule, the indices are numbers used to adjust the Relative Value Units for each component of a service (physician’s work, practice’s overhead, and malpractice costs) to reflect geographic differences in cost to provide the services. Each component is multiplied by its own GPCI. The GPCI is a single measure that combines the three fixed shares, whereas the geographic adjustment factor (GAF) of the Medicare fee schedule allows for each service to reflect different shares, thus creating a GAF for each service.

Adjusted length of stay for all-patient allowances (diagnosis-related groups [DRGs]) for outliers, transfers, and negative outliers that would otherwise skew the data. The GMLOS is used to establish the per diem payment only for transfer cases.