Purpose: In longitudinal studies, parents are the most accurate source of information on young children's dietary intake; for older children, questioning children themselves may be more appropriate. However, if parental reports for young children and self-reports of older children are to be used in the same analyses, the measures must be comparable.
Methods: During school hours, fourth and sixth graders in 14 Flemish (Belgium) primary schools completed an online 15-item food frequency questionnaire with a retest questionnaire one to two weeks later; parents completed a paper-and-pencil or online questionnaire. Test-retest data were available for 286 children; children's tests could be matched to parents' reports for 275 children.
Results: On average, test-retest correlations were 0.68 (grade 4: 0.63; grade 6: 0.71) and correlations between children's and parents' reports were 0.44 (grade 4: 0.39; grade 6: 0.49). No systematic differences were found between the test and retest. Comparison of children's and parents' reports resulted in significant differences for six of the 15 items.
Conclusions: Low consensus between parents' and children's reports for several items may impede comparisons at a group level. Additionally, the results indicate more optimal dietary assessment in sixth graders.