relationship holds on average, Dr. Dudley pointed out that most individuals could benefit from this information. On a case-by-case basis, however, the information will not have its intended consequences for a significant share of patients. Dr. Hannan provided two examples of the risk of making referrals purely on the basis of volume. He noted that in New York, one-third of high-volume surgeons (i.e., those performing at least 150 procedures per year, or 450 procedures over 3 years) 5 had higher-than-average risk-adjusted mortality rates. Also among the 18 hospitals performing very high volumes of angioplasty (i.e., at least 400 procedures per year),6 8 hospitals had above average risk-adjusted mortality rates. As these examples illustrate, a relatively large share of patients would be cared for by providers with inferior performance if referrals were made solely on the basis of volume.

Dr. Dudley noted that providing consumers with information to support decision-making has been somewhat disappointing. Report cards can be difficult for consumers to understand and, where they have been published, appear to have been used by only a small percentage of consumers. New formats and communication tools are needed to improve their use, and Dr. Dudley suggested that a Consumer Reports model be tested for disseminating information. Consumer Reports represents a trusted, unbiased source of information that provides a wealth of detailed information, as well as easy-to-use summary measures with which to judge products. According to Dr. Dudley, the inclusion of information on functional status, long-term outcomes, and common chronic conditions (e.g., those treated in outpatient settings) would likely increase the relevance of such reports to consumers.

Large purchasers are beginning to hold systems of care accountable for quality improvement. The Pacific Business Group on Health (PBGH), a large purchasing coalition, provides condition-specific volume data for area hospitals on its website ( along with guidance on how to interpret the data. PBGH also requires health plans to ensure that patients with selected conditions go to high-volume hospitals. This approach is also being taken by the Leapfrog Group, a newly formed organization comprising many large employers and purchasing coalitions (including PBGH). The Leapfrog Group has developed a set of health plan performance standards that include volume standards for specific conditions, but it will recommend better measures when they become available

Information about volume can be applied without public disclosure, for example, within systems of care for quality improvement programs. Low-volume providers may withdraw voluntarily to avoid scrutiny or be motivated to examine and improve internal structures or processes of care.

Dr. Dudley and colleagues described several potential barriers to implementing a selective referral program based on a volume standard:

  1. a potential for decrements in quality at higher volumes;

  2. patients' preferences for care close to home;

  3. patients' lack of resources to travel to hospitals that are far away;

  4. patients who need immediate treatment or are too unstable to transfer;

  5. loss of access in areas where low-volume services have been closed (e.g., cardiac surgery);

  6. resistance from physicians and hospitals to cooperate in quality monitoring efforts; and


According to these criteria, 30 percent of cardiac surgeons in New York are high-volume providers.


The American College of Cardiology recommends that hospitals perform at least 200 angioplasty procedures per year.

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