How is CMI calculated from DRG weights?

• A. Sum of DRG weights divided by number of discharges
• B. Maximum DRG weight among discharges
• C. Average DRG relative weight across discharges
• D. DRG weight per patient multiplied by LOS

Answer: (C)

CMI measures the average resource intensity of a hospital’s patient mix, using DRG relative weights. To get it, sum the DRG weights for all discharges and divide by the number of discharges, yielding the average DRG weight per patient. This is why the correct description is the average DRG relative weight across discharges. It reflects overall case mix rather than total volume, a single high-weight case, or any factor like length of stay. The concept hinges on using relative DRG weights to represent typical resource use per patient.