accurate—that the other institutions were not different one from the other? As can be seen in Figure 3A-4, three other hospitals (Bellevue, Erie County, and Upstate Medical) had less good outcomes as well, but with slightly less certainty than the three already noted. The arbitrary designation of a P-value (here of less than 0.05, but it could be any a priori P-value) has led to the erroneous general impression that only the first-named three hospitals are somehow "different" and are to be regarded as outliers.
The criticism can be generalized: Why should "the ruler"—in this case an arbitrary P-value—not be placed so that St. Luke's, Arnot-Ogden, and Long Island Jewish are included as outliers? Where, indeed, ought the ruler, if applied to Figure 3A-4, be brought to rest?
Public release of information about the variability in the ranks of various hospitals that is produced by different methods of analysis helps the public to understand the degree of uncertainty in overall inferences about "the best place to go for surgery." Much of this can be expressed in some combined index (in Figure 3A-4, this is the risk-adjusted percentage mortality). Depicting other information, and displaying information in bar diagrams (see, for instance, Figures 3A-5, 3A-6, and 3A-7) encourages, if not forces, the public to see how complex a matter it is to distinguish between the best and the worst (or better and poorer) hospitals. It also portrays the small differences that sometimes separate these facilities. Thus, this committee believes that HDOs must realize that the fairest approach to the public release of evaluative information involves disclosing rankings—of all actual data as well as derived data—along with appropriate explanations.
The knowledge base on effective ways to communicate and disseminate quality-related information to consumers is comparatively scanty, yet much health policy today presumes that health care policymakers and providers understand how to carry out such efforts. To overcome gaps in this area, more than one research agenda in the quality-of-care arena has specifically called for work on information dissemination techniques (IOM, 1990; VanAmringe and Shannon, 1992). The committee endorses these calls for additional research on these topics.