US · guidance
CMS Pub. 100-16, ch. 8, § 60.3.1
Calculation of ISAR Factors and Payment Rates
The following calculations are performed in the MA bid pricing tool. Plan-specific county
ISAR factors are developed, both for local and regional plans, according to a formula that
ensures that the plan-specific county rates tie back to the plan’s bid, and these factors are
applied to the plan bid.
ISAR Factors - The county ISAR factor is the ratio of the MA capitation rate for the
county to the weighted average of all MA capitation rates in the plan’s service area. The
weights used for both local and regional plans ISAR factors are the plan’s projected
enrollment in each county.
The weighted average of all the county ISAR factors for a plan’s service area must equal
1.0.
Payment Rates - For multi-county local plans and for regional plans, each plan-specific
county payment rate equals the standardized A/B bid multiplied by the county ISAR factor.
Each county in the plan’s service area has an ISAR factor and a plan-specific payment rate.
History
(Rev. 89; Issued: 11-02-07; Effective/Implementation: 11-02-07)
Provenance
- Source
- cms.gov
- Retrieved
- 2026-08-25
- Edition
- iom-2026-08-25
- Content hash
50801c5fd8e588df67fc35ae643cacba63b04d557720ee9123e29b16306fea7a
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