What is Blended National Average Risk Score? Definition, Formula, and Benchmark

The blended national average risk score is CMS's published reference point for aggregate Medicare Advantage risk scoring. By model construction the average risk score across the MA population should approximate 1.00; the blended national average captures the actual empirical average across all MA enrollees weighted appropriately by enrollment and payment-year variables. It is the denominator context for reading any plan-level RAF number.

A plan with an average RAF of 1.18 has a population that is approximately 18% sicker than the MA average. Against the FFS reference that originally calibrated the model, the plan's members consume about 18% more expected cost than an average Medicare beneficiary; against the actual MA population, the plan's members are 18% above what the blended national average would produce. Both framings are useful for different analytical purposes.

CMS publishes the blended national average as part of the Advance Notice and Rate Announcement cycle. It updates annually as the MA population grows, demographics shift, and coding patterns evolve. The number has drifted slightly above 1.00 in most recent years as MA enrollment has skewed toward chronically ill beneficiaries and as coding intensity has risen; the normalization factor partially corrects for this drift to keep the payment-relevant baseline stable.

For plans and provider groups, the national average functions as a benchmark. A plan with RAF of 0.85 has members materially healthier than average — which in MA economics can be a concern (lower risk-adjusted revenue per member without a corresponding lower cost profile) or an opportunity (if the plan operates efficiently, the revenue compression may be offset by lower utilization). Analysts typically compare plan RAF trajectory against the national average trajectory to separate real acuity changes from systemic MA-population changes.

Geographic variation in RAF is substantial. Markets with older demographics and higher chronic-condition prevalence run 10–20% above the national average; healthier markets run 10–20% below. Regional plan benchmarking should use regional comparators rather than national averages when geographic variation is the driver of interest.

V28 transition affected the blended national average calculation. The blended model produces a blended national average, with contributions from V24 and V28 components weighted per the transition schedule. Programs reading blended averages during 2024–2025 should note the blend composition; post-2026 readings are pure V28.

From a board-reporting standpoint, Blended National Average Risk Score belongs in the compliance committee's quarterly dashboard. The reporting line should include volume, exception rate, and any open remediation action; reviewers tie Blended National Average Risk Score metrics to the broader compliance program KPIs so an emerging Blended National Average Risk Score risk surfaces before it becomes a formal finding. Pairing the Blended National Average Risk Score trend with raf score gives the committee a single view of whether the control environment is strengthening or drifting.