because initiation rather than cessation is thought to be the dominant force for young people.
Measures should be both valid and reliable and both sensitive and specific (Sofaer, 1995). Practical problems often require compromises in these respects. Healthy People 2000 Objective 15.1 on coronary heart disease exemplifies the problem. The objective addresses the coronary heart disease mortality rate because this component of overall cardiovascular mortality is the most amenable to prevention efforts. The specific grouping of diagnostic codes used to define coronary heart disease is not, however, routinely available in vital statistics reports. In many communities, it might be more appropriate to measure progress in terms of readily available cardiovascular mortality rates, while bearing in mind that reduction beyond a certain point is unlikely.
Lacking population-based data on the incidence or prevalence of specific diseases, performance measure developers often think about using numbers of people receiving treatment for the disease in question. For instance, Healthy People 2000 Objective 15.3 calls for a reversal in the increasing number of people with "end-stage renal disease (requiring dialysis or transplantation)." The baseline figures cited, however, count the number of people receiving dialysis or transplantation, not those requiring it. Thus, these trends reflect changes in diagnostic and treatment patterns as well as access through an expanding federal program, and it is doubtful whether future changes in the data can be attributed to the success of prevention activities as intended by Healthy People 2000. In certain circumstances, however, hospital treatment data can yield appropriate performance measures. For instance, an Institute of Medicine (IOM, 1993) report on measuring access to health care identifies a number of "ambulatory care sensitive conditions" for which hospital admissions should be avoidable if individuals have access to appropriate ambulatory care.
When a performance measure calls for action by a number of similar entities in the community such as schools, work sites, and health care plans, there are basically two ways to create performance measures. A community can measure the proportion of entities taking the action, as in Objective 3.11 of Healthy People 2000:
Increase to at least 75 percent the proportion of worksites