Analysis of item response and differential item functioning of alcohol expectancies in middle school youths.

Drinking behavior in preadolescence is a significant predictor of both short- and long-term negative consequences. This study examined the psychometric properties of 1 known risk factor for drinking in this age group, alcohol expectancies, within an item response theory framework. In a sample of middle school youths (N = 1,273), the authors tested differential item functioning (DIF) in positive and negative alcohol expectancies across grade, gender, and ethnicity. Multiple-indicator multiple-cause model analyses tested differences in alcohol use as a potential explanation for observed DIF across groups. Results showed that most expectancy items did not exhibit DIF. For items where DIF was indicated, differences in alcohol use did not explain differences in item parameters. Positive and negative expectancies also systematically differed in the location parameter. Latent variable scale scores of both positive and negative expectancies were associated with drinking behavior cross-sectionally, while only positive expectancies predicted drinking prospectively. Improving the measurement of alcohol expectancies can help researchers better assess this important risk factor for drinking in this population, particularly the identification of those with either very high positive or very low negative alcohol expectancies. Copyright 2009 APA, all rights reserved.