A psychometric analysis of the Daily Drinking Questionnaire in a nationally representative sample of young adults from a Mediterranean drinking culture.

To examine psychometric properties of the Daily Drinking Questionnaire (DDQ) in a Mediterranean "wet" drinking culture. Three studies were conducted using random samples drawn from a representative sample of Italian young adults (N = 5,955; females = 62%; mean age = 27): Study 1 explored the factorial structure of weekly alcohol consumption; in Study 2 multi-group confirmatory factor analysis tested measurement invariance across gender; Study 3 applied item response theory analysis to: a) assess how each item discriminated between different alcohol consumption levels; and b) determine if drink propensity on a given day of the week varied according to individual characteristics. In Study 1, a one-factor solution with no clear differentiation between weekdays and weekend alcohol use was found. Study 2 confirmed measurement invariance of the one-factor solution across gender. Results of Study 3 indicated that alcohol use on weekdays (Monday to Thursday) provided more information on overall alcohol consumption than alcohol use on weekends (Friday to Sunday). Cultural differences of alcohol use are reflected in relatively simple alcohol measures, such as the DDQ. In contrast with peers from "dry" drinking cultures, Italian young women and men do not clearly differentiate between weekdays and weekend drinking. In Italy, the DDQ best captures participants' average alcohol consumption levels rather than light or heavy, and should be used in national epidemiological research accordingly.