Case Mix Index

The Case Mix Index (CMI) is the average relative DRG weight of a hospital’s inpatient discharges, calculated by summing the Medicare Severity-Diagnosis Related Group (MS-DRG) weight for each discharge and dividing the total by the number of discharges. The CMI reflects the diversity, clinical complexity, and resource needs of all the patients in the hospital. A higher CMI indicates a more complex and resource-intensive case load. Although the MS-DRG weights, provided by the Centers for Medicare & Medicaid Services (CMS), were designed for the Medicare population, they are applied here to all discharges regardless of payer. Note: It is not meaningful to add the CMI values together.

Data and Resources

Field Value
accessLevel public
catalog_@context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
catalog_conformsTo https://project-open-data.cio.gov/v1.1/schema
catalog_describedBy https://project-open-data.cio.gov/v1.1/schema/catalog.json
identifier 4e3e135e-7a01-45c1-90d9-971b8a9e5092
issued 2017-06-16T22:30:35.826295
modified 2022-04-22T15:28:18.891419
publisher Department of Health Care Access and Information
resource-type Dataset
source_datajson_identifier true
source_hash d69be5f05ac56fbca89aafa4b813cbf02779b5df
source_schema_version 1.1
theme {"Health and Human Services"}
Groups
  • AmeriGEOSS
  • National Provider
  • North America
Tags
  • acuity
  • amerigeo
  • amerigeoss
  • case-mix-index
  • ckan
  • cmi
  • department-of-health-care-access-and-information
  • diagnosis-related-group
  • drg
  • geo
  • geoss
  • hcai
  • ms-drg
  • msdrg
  • national
  • north-america
  • united-states
  • weight
isopen False
license_id notspecified
license_title License not specified
maintainer Department of Health Care Access and Information, Healthcare Analytics Branch
maintainer_email dataandreports@hcai.ca.gov
metadata_created 2025-11-21T01:45:20.662036
metadata_modified 2025-11-21T01:45:20.662040
notes The Case Mix Index (CMI) is the average relative DRG weight of a hospital’s inpatient discharges, calculated by summing the Medicare Severity-Diagnosis Related Group (MS-DRG) weight for each discharge and dividing the total by the number of discharges. The CMI reflects the diversity, clinical complexity, and resource needs of all the patients in the hospital. A higher CMI indicates a more complex and resource-intensive case load. Although the MS-DRG weights, provided by the Centers for Medicare & Medicaid Services (CMS), were designed for the Medicare population, they are applied here to all discharges regardless of payer. Note: It is not meaningful to add the CMI values together.
num_resources 4
num_tags 18
title Case Mix Index