Convergent Validity of the Previous Day Physical Activity Recall and the Activitygram Assessment

This study evaluated the convergent validity of the Previous Day Physical Activity Recall (PDPAR) and the computerized activity assessment from the Cooper Institute (ACTIVITYGRAM) usingaseline data from a large behavioral intervention study (Healthy Youth Places Project). A sample of 6th grade children (n = 135) from eight different schools wore a Biotrainer activity monitor and completed the PDPAR assessment on three subsequent days. At the end of the three days, students from two of the schools (n = 53) also completed the ACTIVITYGRAM recall. Data from the Biotrainer were checked for compliance (11 excluded) and processed in 30 minute time blocks to correspond temporally with the time intervals from the PDPAR and the ACTIVITYGRAM. Data were further summed into segments (afternoon, evening and all day) in order to examine the patterns among the measures. The mean bouts of activity per day (Moderate or Hard categories) for the PDPAR and the ACTIVITYGRAM were 1.98 and 2.01, respectively and no significant differences were observed across any of the three days (p > .01). Average correlations between PDPAR activity bouts and summed Biotrainer counts were .52, .30 and .46 for the afternoon, evening and whole day time periods, respectively. Comparable values for the ACTIVITYGRAM were .66, .39 and .54. Correlations between the number of reported bouts on the PDPAR and the ACTIVITYGRAM were .82, .67 and .52 for the three days. These correlations may be artifically low due to the categorical nature of the self-report data. When the individual intensity ratings (Rest, Light, Moderate and Hard) from each 30 minute interval were compared the classification agreement between the ACTIVITYGRAM and the PDPAR were 82.4%, 81.5% and 79.9% for the three days. The majority of the misclassifications (10–12%) were due to discrepancies between Rest and Light activity codes. This study supports the validity of the PDPAR and the ACTIVITYGRAM and suggests that they provide similar information about activity patterns in children. Supported by NIH 5 RO1 HD37367–02 (NICHD, NINR, ODP, NIAID, ODS).