The food intake recording software system is valid among fourth-grade children.

Objectives: To assess the validity of the Food Intake Recording Software System (FIRSSt) against observation of school lunch and a 24-hour dietary recall (24hDR); and to test the effects of sequencing, observation and a hair sample as a bogus pipeline on accuracy of dietary report.

Design: Six-group design systematically varying sequence of self-report (FIRSSt vs 24hDR), observation of school lunch and hair sample as a bogus pipeline manipulation, with random assignment of participants.

Subjects/setting: 138 fourth-grade students in 2 elementary schools.