The recall of physical activity: using a cognitive model of the question-answering process.

Issues related to the validity and reliability of self-reports of physical activity are an important consideration in assessing the relation between physical activity and various health outcomes that are of interest to epidemiologists. This paper examines the case for incorporating survey methods procedures into the development, refinement, and administration of instruments designed to obtain self-report information on physical activity. In doing so, we present a method of question analysis that enables researchers to identify potential cognitive difficulties with a question and then identify possible methods for improving data quality that have successfully improved the validity of survey instruments in other areas. In doing this, we review portions of the literature in cognitive psychology devoted to autobiographical memory and discuss methods that have emerged from this research that enhance the overall validity and reliability of the data obtained in a variety of health-related areas. We also illustrate ways in which these methods can be incorporated into existing physical activity surveys.