Weekly recall and dairy estimates of alcohol consumption in a general population survey

Diary and weekly recall measures of alcohol consumption in a representative sample (N = 399) of the Dutch population are compared. The weekly recall method consisted of a personal interview with questions about actual alcohol consumption on the previous 7 days. The diary consisted of 14 daily self-reports of consumption and followed the interview. The diary method yields estimates of consumption that are on average 22% higher than those based on weekly recall measures, reducing total undercoverage by about 11%. The difference between the two methods cannot be attributed to a variation of consumption over weeks but seems to stem from a difference in accuracy of recall. There was an increase in glasses underreported at the upper levels of consumption, but underreporting did not seem to be of a nonlinear nature. Considering the large individual variation in consumption over weeks, the ranking of individuals according to their self-reports is relatively stable across method.