Case Mix Index

The Case Mix Index ( CMI abbr, Syn case severity index in the DRG system ) describes the average severity of the patient cases measured on a scale that corresponds to the total resource cost. It provides a measure of the relative economic resources expended by all hospital -treated cases dar. significance of the CMI, especially in medical and economic patient classification systems such as Diagnosis Related Groups ( DRG).

It is calculated by adding the relative weights (cost weight, CW ) of each patient case ( total = Case mix (CM ) ) and divided by the number of cases. The case mix is the sum of a hospital billed in a given period relative weights.

Restriction

The CMI reflects only average ratios and says nothing about the average of the distribution of the degrees of severity.

The CMI is relative in comparison criterion for comparison of the cost structure of a hospital, but not an absolute measure of efficiency.