ACP American College of Physicians - Internal Medicine - Doctors for Adults

Effective Clinical Practice

A Primer on HEDIS

Although many people talk about report cards for medical care, there are few working examples. The most prominent is the Health Plan Employer Data and Information Set, better known as HEDIS. Used by over 400 health plans, HEDIS is a set of standardized performance measures intended to help purchasers and patients compare health plans in terms of quality (instead of simply comparing costs).

HEDIS is perhaps best thought of as a standardized test for health plans. As in most standardized tests, different sections test different domains (e.g., mathematics, language skills). Each domain contains a series of performance measures (e.g., individual questions). Table 1 shows the seven HEDIS domains and selected performance measures.

HEDIS measures of greatest interest to clinicians are in the effectiveness-of-care domain. Table 2 lists the performance measures, describes how each is calculated, and reports the most recent averages available for the Alliance of Community Health Plans and the national average (representing all participating plans). In each case, a higher proportion is presumed to represent better care. Some patients, however, may have an informed preference to forgo some of these services, such as certain immunizations (see the article by Mehl in this issue).

The individual performance measures have evolved over time. When HEDIS was initiated in 1991, the effectiveness measures focused on vaccination and screening rates. Measures were added subsequently to reflect treatment quality in diabetic and post­myocardial infarction patients. New measures to examine care of patients with hypertension, asthma, chlamydia, and menopause have been proposed for the next version of HEDIS (Table 3).

As HEDIS performance measures become more complex, so do the questions about measurement methods (e.g., Does a blood pressure of 145/95 mm Hg require control? What constitutes a sufficient discussion of treatment options?).

HEDIS is managed by the National Committee for Quality Assurance (NCQA). NCQA is encouraging the broad use of HEDIS data by employers, consumers, and other health care professionals to compare health plans. Further information can be found at