Accuracy of children's school-breakfast reports and school-lunch reports (in 24-hour dietary recalls) differs by retention interval

BACKGROUND/OBJECTIVES: Validation-study data were analyzed to investigate the effect of retention interval (time between the to-be-reported meal and interview) on accuracy of children's school-breakfast reports and school-lunch reports in 24-hour recalls, and to compare accuracy of children's school-breakfast reports for two breakfast locations (classroom; cafeteria). SUBJECTS/METHODS: Each of 374 fourth-grade children was interviewed to obtain a 24-hour recall using one of six conditions from crossing two target periods (prior 24 hours; previous day) with three interview times (morning; afternoon; evening). Each condition had 62 or 64 children (half boys). A recall's target period included one school breakfast and one school lunch, for which the child had been observed. Food-item variables (observed number; reported number; omission rate; intrusion rate) and energy variables (observed; reported; report rate; correspondence rate; inflation ratio) were calculated for each child for school breakfast and school lunch separately. RESULTS: Accuracy for school-breakfast reports and school-lunch reports was inversely related to retention interval. Specifically, as indicated by smaller omission rates, smaller intrusion rates, larger correspondence rates, and smaller inflation ratios, accuracy for school-breakfast reports was best for prior-24-hour recalls in the morning, and accuracy for school-lunch reports was best for prior-24-hour recalls in the afternoon. For neither school meal was a significant sex effect found for any variable. For school-breakfast reports, there was no significant school-breakfast location effect for any variable. CONCLUSIONS: By shortening the retention interval, accuracy can be improved for school-breakfast reports and school-lunch reports in children's 24-hour recalls.