The impetus for this study arose from the need to upgrade the case mix measure of choice in use at the national level in Ireland. Since 1993, various versions of the DRG grouper supported by the Health Care Financing Administration (HCFA) had been in use in Ireland. With improvements in available data, together with developments in the range and quality of alternative groupers available, it was considered timely to test performance of the alternative options on discharge abstract data for Irish hospitals. The groupers selected for testing included four versions of the Australian Refined (AR) DRGs, the AP DRGs (V18.0), CMS DRGs (V20) and IR DRGs (V1.2). Results for the HCFA DRGS (V16.0) were also included for purposes of compariso
