Figure 1.

The sequence of activities captured in the Sleep module: recall vs record. (A) Recalls collected dietary information from the previous day. When respondents complete a dietary recall with the Sleep Module, information is gathered on the sleep periods immediately preceding and immediately following the dietary reporting period. First, two questions are asked about wake time and sleep quality for the sleep period immediately preceding the first reported meal of the recall day. The same two questions are asked again along with the other eight sleep questions for the sleep period immediately after the last meal of the recall day. (B) Records collect dietary data in real time. When respondents complete a food record with the Sleep module, all 10 sleep questions are asked about the sleep period before the first meal of the record day. The collection of multiple, consecutive records with the Sleep module allows researchers to assess consecutive nights of sleep.