Inpatient Definitions and Methodology

Patient Origin

All information in this report is from the Medicare Hospital Market Service Area File which is updated annually by CMS. The file includes Medicare discharges, patient days, and gross charges by ZIP code for each hospital.  Data are based on 100% of all Medicare claims (i.e. both fee-for-service and Medicare Advantage) during a calendar year.

The ten ZIP codes with the highest number of Medicare discharges are detailed and statistics for all other ZIP codes are summarized for a hospital:

  • The percentage increase or decrease in Medicare discharges is calculated by comparison with the hospital's discharges during the prior year.
  • The market share is calculated by comparison with all other hospitals having Medicare discharges from the ZIP code (i.e. the hospital's discharges from a ZIP code as a percentage of total discharges to all hospitals from the ZIP code).
  • The market share 5-years prior is calculated in the same fashion as market share, but using Service Area File data from five years prior. For example, 2014 data would be used for this field when 2019 data is the most current period reported.

PLEASE NOTE: Data derived from the Hospital Market Service Area File are not equivalent to MedPAR claims data used elsewhere by ahd.com. This is due to differences in reporting periods (i.e. calendar year vs. fiscal year) and differences in patient populations reported (i.e. all Medicare claims vs. only fee-for-service claims).