Paying organizations fairly for the patients they actually serve depends on accurately capturing how sick those patients are. Risk adjustment is the quiet machinery that makes value-based payment workable, and it can fail in both directions.
If you pay an organization a fixed amount to care for a population, you have to answer an obvious question first: how sick is that population? A practice caring for frail, complex patients should not receive the same payment as one caring for the generally healthy. Risk adjustment is the method that accounts for this difference, translating patients’ documented health status into a score that predicts their expected costs relative to an average patient. Without it, any prospective or shared-risk payment model would systematically punish the organizations that take on the hardest cases.
How it works
Medicare’s approach, the Hierarchical Condition Category (HCC) model, builds risk scores from diagnoses recorded across inpatient, outpatient, and physician encounters, combined with demographic factors such as age. The result lets payers compare and adjust payments for populations with very different health profiles. The same logic underpins risk-bearing arrangements across Medicare Advantage, Medicaid, and commercial contracts. The principle is simple even where the formulas are not: payment should follow need.
Why the stakes are high
Risk adjustment can fail in two opposite directions, and both matter.
Under-capture penalizes the right behavior. When a clinician treats a complex patient but the patient’s conditions are not fully and accurately documented, the organization looks like it is spending too much on a seemingly healthy person. Over time, that distorts performance comparisons and can quietly pull resources away from the practices serving the sickest patients.
Over-capture corrodes trust. When documentation is driven by revenue rather than clinical reality, risk scores inflate, payments rise, and the model’s credibility erodes. The goal is not to maximize a score; it is to record the truth of a patient’s health completely and accurately.
A quiet equity issue
Because risk adjustment determines whether caring for sicker, more complex, and often more disadvantaged patients is financially viable, it is also an equity question, and the measurement framework in Measuring Equity in Value-Based Care depends on getting it right. Models that fail to account for the real burden of illness, and the social circumstances that shape it, can make safety-net providers appear inefficient and weaken the case for serving the communities that need the most. Getting risk adjustment right is therefore not a back-office technicality. It is a precondition for value-based care that is fair to patients and to the organizations willing to care for them.