Validation of a Previous Day Recall Measuring Time Spent in Physically Active and Sedentary Behaviors

Test the validity of a PDR administered by phone against a valid reference measure. Adolescents (n=91; 12-17 yrs; 53% female) and adults (n=88; 18-71 yrs; 55% female) wore an activPAL (aPAL) for 7 days to measure sedentary (sit/lie) and active time (standing/stepping) and completed up to three PDRs. Interviewers conducted PDRs eliciting open-ended reports of time spent sleeping and in specific active and sedentary behaviors at home, work/school and in the community. Bland-Altman methods and measurement error models evaluated PDR validity versus aPAL on days matched by date and observation time. Adolescents and adults reported 10.0 (SD=2.2) and 9.9 (SD=2.8) hr/d of sedentary time, and 4.2 (SD=1.8) and 5.2 (SD=2.6) hr/d of active time, respectively. Total PDR active and sedentary time was greater than aPAL wear time (difference=0.58 hr/d, p0.05) negative bias for active time in adolescents (bias=-0.27 (SD=1.37) hr/d) and adults (bias=-0.13 (SD=1.44) hr/d).