Evidence to Support the Use of the Retrospective Pretest method to Measure Dietary and Physical Activity Behavior and Self-Efficacy in Adolescents

Abstract

This study compared the retrospective pretest-posttest method to the traditional prospective pretest-posttest method assessing adolescents’ dietary and physical activity, self-efficacy and behaviors. Participants were 7th and 8th grade students at a rural K-8th grade elementary school in Northern California (n=188). All participants completed an evaluation instrument (traditional pretest), followed by a 9-lesson dietary and physical activity intervention. Upon completion of the intervention, participants completed a second and identical evaluation instrument which served as a traditional posttest. The following day, participants completed another evaluation tool, this time formatted as a retrospective pretest. Analysis included sample t tests comparing the means of each method. Participants (n = 154) with a mean age of 13 ± .7 years old were included in the analyses (52% female). Paired sample t tests reported non-significant differences between the two methods for dietary behavior and dietary self-efficacy, yet significant differences were found for physical activity behavior (p < .05) and physical activity self-efficacy (p < .01). We conclude that the retrospective pretest-posttest method was as good a measure of dietary self-efficacy and behavior as the traditional prospective pretest-posttest method and may be better at attenuating response-shift bias when assessing physical activity self-efficacy and behavior.