Reliability and Validity of Survey Data on Physical Health

Abstract

HOW consistently do people answer ques- tions about their health when a survey is repeated after a short interval?How closely does the information collected by survey agree with that obtained from clinical records?This paper evaluates survey data on physical health from these two points of view.The two meth- odological studies discussed are part of a re- search program conducted by the Human Population Laboratory of the California State Department of Public Health and supported by grants from the Public Health Service.In 1965 health data were collected by self- administered questionnaires from a large probability sample of adults in Alameda County, Calif. Known as the Survey of Health and Ways of Living, this baseline survey is the first of a projected series in a longitudinal study of physical, mental, and social health in the county.The study's purpose is to assess the re- lation between health, understood in a broad generic sense, and a wide range of demographic, economic, familial, cultural, and environmental factors and personal habits, which for con- venience are referred to collectively as "ways of living."A primary hypothesis in this study is that in