US · guidance
CMS Pub. 100-04, ch. 3, § 140.2.3
Case-Mix Groups
In general, a case will be grouped into a Case-Mix Group (CMG) based on the clinical
characteristics of the Medicare beneficiary. Rehabilitation Impairment Categories (RICs),
functional measurements, age, and comorbidities were used to develop the CMGs.
Specifically, RICs are used to group cases that are similar in clinical characteristics and
resource use. The RICs are codes that indicate the primary cause of the rehabilitation
hospitalization and are clinically homogeneous. In addition to the first two digits of the
CMG indicating the RIC, the CMGs are further partitioned using functional measures of
motor and cognitive scores. Age improves the explanatory power of the CMGs if some
groups are split based on this variable. Lastly, comorbidites were found to substantially
increase the average cost of a case in specific CMGs. The comorbidities are arrayed in
three categories (or tiers) based on whether the costs are considered high, medium, or low.
If a case has more than one comorbidity, the CMG payment rate will be based on the
comorbidity that results in the highest payment.
History
(Rev. 2673, Issued: 03-14-13, Effective: 04-22-13, Implementation: 04-22-13)
Provenance
- Source
- cms.gov
- Retrieved
- 2026-08-25
- Edition
- iom-2026-08-25
- Content hash
4d8c8bc66e7bc23164fc80a6ae8b58fa7d210bee1358d30910414f4bbcc9e0ae
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