HEDIS Measures Explained: A Practical Guide for Practice Leaders and Quality Teams

Medically reviewed by Dr. Charles Sweet, MD, MPH, board-certified psychiatrist and Medical Advisor at Linear Health.

HEDIS stands for the Healthcare Effectiveness Data and Information Set. It is the most widely used set of standardized performance measures in U.S. healthcare, applied to more than 200 million people every year. If you operate in Medicare Advantage, Medicaid managed care, or a commercial value-based contract, your reimbursement depends on HEDIS performance whether you have ever read the measure specifications or not.

This guide explains what HEDIS is, who uses it, the six domains, the 15 measures most practices should focus on, and the operational playbook for improving scores without hiring a quality team you cannot afford.

What is HEDIS and who runs it?

HEDIS is a set of standardized performance measures developed and maintained by the National Committee for Quality Assurance (NCQA). NCQA is a private, not-for-profit organization that has accredited health plans and developed quality measures since 1990. HEDIS measures are revised annually through a public comment process, with new measure years (e.g., HEDIS Measurement Year 2026) released in the summer prior to the year they cover.

Health plans report HEDIS scores to NCQA, which audits them and publishes results. CMS uses a subset of HEDIS measures to calculate Medicare Advantage Star Ratings. State Medicaid programs use HEDIS for managed care organization quality reporting and bonus calculations. Commercial purchasers use HEDIS scores to evaluate plans during procurement.

The mechanical chain is health plan to provider to patient. Plans report HEDIS. Plans push HEDIS performance to contracted providers through quality bonus payments. Providers chase HEDIS gaps in their attributed populations. Patients receive (or don't receive) the recommended services that move the numbers.

What are the six HEDIS domains of care?

HEDIS measures organize into six domains.

1. Effectiveness of Care. The largest domain. Includes preventive screenings, chronic disease management, behavioral health treatment, and medication management.
2. Access and Availability of Care. Measures of whether members can get appointments and care when they need them.
3. Experience of Care. Member-reported satisfaction with care and the health plan, primarily through CAHPS surveys.
4. Utilization and Risk-Adjusted Utilization. Inpatient days, ED visits, ambulatory visits, and risk-adjusted variations.
5. Health Plan Descriptive Information. Plan-level information about enrollment, board certification, language access, and similar attributes.
6. Measures Reported Using Electronic Clinical Data Systems (ECDS). A growing category that uses EHR data instead of claims, including measures for behavioral health follow-up and prenatal care.

For practice operations, the Effectiveness of Care domain is where most of the work happens.

Which 15 HEDIS measures matter most for primary care and specialty practices?

The full HEDIS measure set runs over 90 measures across the six domains. Most practices will not be evaluated on all of them. The 15 below are the most commonly used in U.S. value-based contracts.

The specific measures that matter most for your practice depend on your contracts. A pediatric practice cares about CIS, IMA, W30, and WCV. An FQHC cares about cancer screenings, CDC measures, and immunizations. A behavioral health practice cares about AMM, FUH, and SUPD. The starting point is reading your payer contracts and identifying the measures explicitly named in quality bonus arrangements.

How are HEDIS scores actually calculated?

HEDIS measures use one of three reporting methods.

Administrative measurement. Calculated entirely from claims and encounter data. Fast, fully automated, and what most measures use. The downside is that anything not captured in claims (e.g., a screening done outside the network) doesn't count.

Hybrid measurement. Combines claims data with manual chart abstraction from a sample of records. Used when claims data alone misses too many services. Hybrid is more accurate but operationally expensive because it requires nurse abstractors reviewing charts.

Electronic Clinical Data Systems (ECDS). Pulls measure data directly from EHRs and HIEs. Growing category. NCQA is moving more measures to ECDS reporting because it captures clinical data that claims miss.

Each measure has specific CPT, HCPCS, and ICD-10 codes that identify both the eligible population (denominator) and the service completion (numerator). Coding errors are one of the largest reasons HEDIS scores underperform what practices are actually delivering. A diabetic eye exam done by an optometrist who codes incorrectly is invisible to the measure even though the service happened.

What changed in HEDIS Measurement Year 2026?

The HEDIS MY 2026 release retired several measures and modified specifications across multiple others. Two operationally relevant changes for practices.

Medicare-Medicaid Plans (MMP) reporting was removed. MMPs are no longer a reporting option for MY 2026, which simplifies cross-plan reporting for organizations that previously had to maintain duplicate data flows.

Health Plan Descriptive Information measures expanded. A newly introduced measure plus updates to existing reporting elements add reporting burden for plans, which translates downstream into more documentation requests landing on contracted providers.

For practices, the practical implication is that measure specifications change every year. The team responsible for HEDIS performance needs to track NCQA updates and update workflows accordingly. A practice that ran the same measure-closure workflow in 2024 and 2025 without updates is likely chasing the wrong codes by 2026.

Why do most practices underperform on HEDIS?

The performance gap rarely comes from clinical care quality. Most practices deliver the services. The gap comes from three operational failure points.

Data fragmentation. Patients receive services across multiple practices, labs, imaging centers, and pharmacies. The mammogram happens at the imaging center. The flu shot happens at CVS. The eye exam happens at an unaffiliated optometrist. None of those services automatically flow back to the attributed PCP's quality reporting unless data exchange is functioning, which it often is not.

Patient outreach gaps. Knowing a patient has an open gap is not the same as getting them in. Most practices identify gaps in claims data 60 to 90 days after the missed service window. By the time outreach begins, the measurement year is half over and the patient has missed multiple touchpoints where the service could have been recommended.

Coding and documentation gaps. Services delivered but not coded correctly are invisible to HEDIS. The most common pattern is a clinician who completes the recommended service but documents it in narrative notes without linking the appropriate CPT or ICD-10 codes to the encounter.

For an honest read on how this plays out in a federally qualified health center environment, our HEDIS measure improvement guide for community health centers covers the operational workflow with case study data.

How do practices improve HEDIS scores without hiring a bigger quality team?

Performance improvement breaks into four operational moves.

1. Identify gaps continuously, not at year-end. Pull payer gap files monthly. Cross-reference against EHR data to remove false positives. Maintain a continuously refreshed list of patients who actually have open gaps.

2. Run multi-channel outreach matched to patient preference. Letters convert below 5%. Outbound staff calls cap at the volume your team can dial. SMS plus voice AI plus secure portal messaging reach 50 to 70% of patients within 9 minutes when channel matches preference. For Medicaid populations or non-English-speaking panels, multilingual outreach is required, not optional.

3. Close the loop at the moment of contact. A patient who agrees to schedule but cannot get an appointment in the next two weeks frequently disengages. Closing-call workflows that book the appointment during the same conversation outperform call-back workflows by 2 to 3x.

4. Validate documentation and coding before year-end submission. Many “open” gaps are documentation errors. A 30-minute coding audit on a sample of attributed patients often uncovers 15 to 25% of “open” gaps that were already closed clinically.

“Linear Health completely transformed how we operate. They replaced five disconnected tools we were using to manage referrals, scheduling, and patient outreach. It's transformed how we operate.”

Where HEDIS automation fits (and where it does not)

Best fit:

• Practices with HEDIS-tied contracts (MA, Medicaid managed care, commercial VBC)
• Multi-payer panels with payer gap files arriving in different formats
• Quality teams of fewer than 5 FTEs managing more than 10,000 attributed lives
• FQHCs reporting UDS measures alongside HEDIS
• Multilingual patient panels

Less ideal fit:

• Fee-for-service-only practices not in any quality-tied contract
• Single-MA-plan practices where the plan is running effective member outreach
• Practices below 1,000 attributed value-based lives
• Practices without basic EHR data hygiene

Frequently asked questions

What does HEDIS stand for?
HEDIS stands for the Healthcare Effectiveness Data and Information Set, a set of standardized performance measures developed and maintained by the National Committee for Quality Assurance (NCQA).

Who uses HEDIS measures?
Medicare Advantage plans, Medicaid managed care organizations, commercial health plans, and ACOs all use HEDIS or HEDIS-aligned measures. CMS uses a subset of HEDIS measures to calculate MA Star Ratings.

How often are HEDIS measures updated?
NCQA releases an updated measure set every Measurement Year. Practices need to track the annual updates and adjust workflows accordingly. Specifications change. Measures retire. New measures are introduced.

What is the difference between HEDIS measures and Star Ratings?
HEDIS is a measure set. CMS Star Ratings are a 5-star rating system applied to Medicare Advantage and Part D plans. Star Ratings include HEDIS measures, CAHPS member experience measures, HOS health outcomes measures, and operational measures specific to CMS. HEDIS feeds Star Ratings but they are not the same thing.

How accurate is administrative HEDIS reporting?
Administrative measurement underestimates true clinical performance because it misses services delivered outside the network and services not coded correctly. Practices that switch from administrative-only to hybrid or ECDS reporting often see scores improve 5 to 15 percentage points without changing clinical care.

Related reading

• What Are Care Gaps in Healthcare?
• HEDIS Measure Improvement Without Adding Staff
• How FQHCs Are Using AI to Close Care Gaps Faster
• Value-Based Care and Referral Coordination
• Annual Wellness Visit Outreach

See how Linear Health automates HEDIS gap closure →