Here we build from prior work to test the unidimensionality of alcohol use disorders and the use of measures of heavy alcohol consumption in a sample of 7 emergency department (ED) sites in 4 countries, compiled as part of the Emergency Room Collaborative Alcohol Analysis Project[14]. We used exploratory factor analysis (EFA) and item response theory (IRT) to study the latent construct of alcohol use disorder in samples from ED patients from different countries in an effort to replicate the finding that there is a unique factor solution for alcohol use disorders[15]. Secondly, if unidimensionality exists, we will test whether 5+/4+ and other measures of alcohol consumption help to improve alcohol use disorder criteria by adding a criterion in the low-medium spectrum of the disorder, applicable to all four countries included here.
