1. Methods and population

A controlled long-term study to evaluate the efficacy of the periodic health examination, utilizing automated multiphasic screening techniques, is being conducted. A representative sample of approximately 5000 persons aged 35–54 was selected in 1964 and has been urged to undergo annual examinations. The morbidity, mortality, and disability, as well as the utilization of medical care, in this group are being compared to a similar group of persons who have been allowed to seek medical care on their own initiative within the same medical care program. The study design, characteristics of the study population, and the experience in examining the population are described in this report. At the start of the study the population was relatively healthy and experienced very little disability. Approximately 65% of the study group is being examined each year, and 78% of the original group were still under surveillance after 7 years.