HCC Coding and RAF Scores: How to Find the Documentation Gaps That Cost Your ACO Money

Hierarchical Condition Category (HCC) coding drives the Risk Adjustment Factor (RAF) that determines per-member-per-month payment in Medicare Advantage and the benchmark calculation in MSSP / REACH ACOs. Most ACOs and MA-contracted practices lose meaningful PMPM dollars to documentation gaps that an analytics layer can flag in real time. The math is unforgiving.

How HCC drives RAF

Each calendar year, a beneficiary's RAF score is calculated from documented chronic conditions captured during qualifying face-to-face encounters with eligible providers. A patient with diabetes, vascular disease, and CKD has a meaningfully higher RAF than the same patient with just diabetes documented.

Critically: RAF resets every year. A condition documented in 2024 does not carry forward to 2025 RAF unless re-documented during 2025.

Where documentation gaps appear

1. Conditions managed but not documented this year. Patients with prior-year diagnoses who haven't had a qualifying 2026 encounter where the condition was assessed and documented.
2. Suspect conditions on labs / imaging but not coded. A1C above the diabetes threshold without a documented diabetes diagnosis. Persistent eGFR below CKD threshold without a CKD code.
3. Hospitalization documentation that didn't flow to outpatient. The inpatient stay documented a condition (e.g., heart failure). The outpatient problem list never got updated. Next year's RAF doesn't reflect the diagnosis.
4. Specialist-managed conditions invisible to primary care. The cardiologist documents stable CAD; the primary care record doesn't have it. The patient's RAF reflects only what PCP encounters captured.

The analytics views that close the gap

Four views together address most documentation gap revenue:

1. Prior-year-coded conditions not yet recaptured. Patients with HCC codes in 2024 who haven't had a 2026 encounter where that condition was assessed.
2. Suspect conditions from labs / imaging. Pattern-matching on lab values, imaging reads, and medication lists to surface likely undocumented conditions.
3. Inpatient-to-outpatient documentation reconciliation. New inpatient diagnoses missing from outpatient problem lists.
4. Pre-visit prep view. Before each scheduled visit, the prep view shows the patient's suspect / unrecaptured conditions for the provider to address.

The revenue math

For an ACO with 15,000 attributed beneficiaries:

• Average RAF: ~1.05.
• Documentation gap closing: typical lift of 0.05 RAF.
• PMPM impact: ~$45/month at typical risk-adjusted PMPM.
• Annual: ~$540/beneficiary × 15,000 = ~$8.1M in RAF-adjusted revenue.

Not all of that flows to the bottom line — RAF interacts with shared savings calculation in complex ways — but the directional impact is large.

The compliance caveat

HCC documentation must be supported by actual clinical assessment and documentation at the qualifying encounter. Coding a condition that wasn't actually assessed or documented is fraud. The analytics layer's job is to surface candidates for assessment, not to suggest coding conditions that weren't addressed.

See ACO risk stratification for the related operational workflow.