HEDIS, the Healthcare Effectiveness Data and Information Set, is a standardized set of performance measures used by more than 90 percent of U.S. health plans to track how well they deliver care. Managed by the National Committee for Quality Assurance (NCQA), it is one of the most widely used quality measurement tools in American healthcare. HEDIS gives employers, consumers, and regulators a consistent way to compare health plans against each other using the same yardstick.
What HEDIS Actually Measures
HEDIS covers a broad range of clinical and service topics, from preventive screenings and chronic disease management to behavioral health and medication use. Rather than measuring a single aspect of care, it uses dozens of individual measures that together paint a picture of a health plan’s overall performance. Examples include whether children receive lead screenings, whether adults with diabetes get appropriate statin therapy, and whether patients receive timely follow-up after acute care visits for conditions like asthma.
The measures are updated annually. For the 2026 measurement year, NCQA added seven new measures, retired two, and shifted four existing measures to electronic data collection. New additions track things like hospital admissions following outpatient surgeries (orthopedic, general, urologic, and colonoscopy procedures), tobacco use screening for people age 12 and older, and a descriptive measure of disability membership within health plans. These updates reflect a continuing push to capture outcomes that matter to patients, not just whether a process was completed.
How Health Plans Collect the Data
Health plans gather HEDIS data through two primary methods: administrative data and a hybrid approach. Administrative data pulls from electronic records like insurance claims, pharmacy records, lab results, and procedure codes. It is efficient but often incomplete, because a service that was delivered may not show up in a billing record.
The hybrid method supplements administrative data with manual reviews of patient medical charts. NCQA requires this hybrid approach when field testing shows that administrative data alone underestimates performance by more than 5 percent. The gap can be significant. Research published in The American Journal of Managed Care found that administrative-only rates were an average of 20.4 percentage points lower than rates that included chart review, meaning health plans that rely only on claims data can look far worse than they actually are.
When a plan uses the hybrid method, it first checks whether its administrative data produces rates close to expected benchmarks. If the rates fall short, the plan draws a random sample of 411 members from the eligible population and reviews their medical records. That sample size is calculated to give an 85 percent chance of detecting a 5 percent difference between plans.
NCQA is steadily moving toward a third approach: Electronic Clinical Data Systems, or ECDS. This method pulls structured data directly from electronic health records and health information exchanges, reducing the need for manual chart reviews. Several measures that previously used hybrid collection, including lead screening in children and statin therapy measures, now use ECDS exclusively.
How HEDIS Connects to Star Ratings
If you’ve seen the one-to-five star ratings on Medicare Advantage plans, HEDIS is a major ingredient. The Centers for Medicare and Medicaid Services (CMS) Star Ratings program uses 44 unique measures, 12 of which overlap directly with HEDIS. Star Ratings also incorporate patient experience surveys and health outcomes surveys alongside HEDIS clinical measures.
Not all measures count equally. Outcome measures (did the patient actually get better?) carry a weight of 3, while process measures (did the plan order the right test?) carry a weight of 1. Patient experience measures carry a weight of 2 in Star Ratings. CMS uses a clustering algorithm to sort plan performance into five categories, one for each star level. Plans that score well earn higher star ratings, which directly affects their ability to attract enrollees and, for Medicare Advantage plans, can unlock bonus payments from the federal government.
Why HEDIS Matters to You
For most people, HEDIS works behind the scenes. You won’t encounter the acronym at a doctor’s visit, but it shapes the care you receive in concrete ways. When your health plan sends you a reminder to schedule a mammogram, a colorectal screening, or a diabetes checkup, that outreach is often driven by HEDIS targets the plan is trying to meet. Plans that perform well on HEDIS measures can earn NCQA accreditation and higher public ratings, which employers and insurance marketplaces use when deciding which plans to offer.
Because the measures are defined so specifically and used so broadly, HEDIS creates an apples-to-apples comparison that is otherwise hard to find in healthcare. The Office of Disease Prevention and Health Promotion notes that HEDIS data feeds into national health tracking efforts, including Healthy People objectives. When you compare health plans during open enrollment and see quality scores or ratings, there is a good chance those numbers trace back to HEDIS.
The Annual Reporting Cycle
HEDIS follows a structured annual calendar. In the fall, NCQA releases templates and data tools for the upcoming submission year. Health plans spend the winter and spring collecting data, conducting audits, and validating results. By mid-June, plans must submit their finalized data, and independent auditors verify the numbers before they are locked. NCQA then publishes the results, typically releasing updated plan comparisons by midsummer. For the 2026 cycle, final HEDIS submissions are due June 15, and public-facing quality reports are expected in July.
This annual rhythm means the data you see in plan ratings typically reflects care delivered during the prior calendar year. A quality score published in mid-2026, for instance, reflects services and outcomes from 2025.
The Shift Toward Digital Measurement
NCQA is in the middle of a multi-year transition toward fully digital quality measurement. The goal is to reduce the cost and burden of manual data collection while making measures more clinically relevant. Instead of relying on billing codes that may or may not capture what happened during a visit, digital measures pull directly from clinical records, capturing lab values, medications prescribed, and clinical notes in a more complete and timely way.
This transition is happening in phases. Some measures have already moved to ECDS-only reporting, while others, like Transitions of Care, are still being tested to determine how best to represent them digitally. For health plans and provider organizations, the shift requires significant investment in data infrastructure, but the long-term promise is measurement that reflects actual patient care more accurately and with less manual effort.