WAC 182-550-3400. Case-mix index

(1) The medicaid agency calculates the case-mix index (CMI) for each individual hospital to measure the relative cost for treating medicaid and CHIP cases in a given hospital. The CMI represents the relative acuity of the claims. (2) Using medicaid and children's health insurance program (CHIP) admissions data from the individual hospital and the hospital's base period cost report, the agency calculates the CMI by: (a) Multiplying the number of medicaid and CHIP admissions to the hospital for a specific diagnosis-related group (DRG) classification by the relative weight for that DRG classification. The agency repeats this process for each DRG billed by the hospital; (b) Adding together the products in (a) of this subsection for all of the medicaid and CHIP admissions to the hospital in the base year; and (c) Dividing the sum obtained in (b) of this subsection by the corresponding number of medicaid and CHIP hospital admissions. (3) The agency recalculates each hospital's CMI during inpatient hospital rebasing, or as needed.