The potential impact of ischemic heart disease intervention programs has usually been assessed using the dichotomy between those programs targeted to high risk groups and those that are population based, but this distinction does not adequately describe the spectrum of possibilities. Using data from the National Health and Nutrition Examination Survey Epidemiologic Follow-up Study (NHEFS), we assessed the effect of a spectrum of 27 potential interventions on mortality reduction and on an Intervention Index (defined as the number of persons whose risk must change to prevent one death). Using combinations of cholesterol reductions of 20% and decreases in the prevalence of smoking and hypertension of 50%, reductions in mortality varied from 1 to 27% and the Intervention Index varied from 26 to 520. A number of potential interventions were equivalent in their mortality reduction of their Intervention Indexes, despite their affecting differing proportions of the population. The Intervention Index provides some measure of the relative efficiency of programs and points to the comparability of different interventive approaches. In addition, this analysis suggests that the potential impact of intervention programs on mortality will be modest, but that a focus on certain subgroups, such as those aged 40-59 years, can achieve substantial results within those groups, even though the population effect would be minimal.