Abstract: | To examine the reliability of self-reports on prevalence, frequency and quantity of drinking in early adolescents by comparing questionnaires with diary reports. Retrospective data were obtained with a questionnaire after conducting a 1-month daily diary on alcohol use in a sample of 78 early adolescents. Sensitivity, specificity, positive, negative predictive values and correlations were calculated to test whether questionnaire reports corresponded with diary reports. Adolescents reported higher prevalence of drinking in diary reports than questionnaire reports. The sensitivity and negative predicted value of drinking prevalence were low, whereas the specificity and positive predicted value were high. Frequency of drinking reported in diary reports were highly correlated with questionnaire reports, whereas for the quantity of drinking only a moderate correlation was found. No significant differences were found for the average frequency and quantity of drinking between questionnaire and diary reports. Questionnaire reports tend to underestimate the prevalence of drinking in early adolescents compared to diary reports, whereas for frequency and quantity of drinking questionnaire reports proved to be reliable. |