How well do TTM measures work among a sample of individuals with unhealthy alcohol use that is characterized by low readiness to change?

Little is known about the applicability of the transtheoretical model of intentional behavior change (TTM) to individuals with unhealthy alcohol use that is primarily characterized by low readiness to change. This study examined the psychometric properties of short measures by assessing three core constructs of the TTM: the 20-item Processes of Change (POC-20) scale, and short versions of the Alcohol Decisional Balance Scale (ADBS) and the Alcohol Abstinence Self-Efficacy (AASE) scale. A sample of 427 individuals with unhealthy alcohol use (Mage = 30 years, 65% men), identified at job agencies in northeastern Germany, completed all three scales. Item difficulty (d), selectivity (rit), and Cronbach's alpha were calculated. Confirmatory factory analyses were used to test for construct validity and latent mean differences across the stages. The psychometric properties of the 8-item AASE were adequate (d range: 0.59-0.78; rit range: 0.59-0.68; α range: 0.74-0.81), except for one subscale. Most items of the POC-20 and the 10-item ADBS were difficult (dPOC range: 0.08-0.40; dADBS range: 0.21-0.58); selectivity (ritPOC range: 0.26-0.62; ritADBS range: 0.34-0.68) and internal consistency (αPOC range: 0.41-0.76; αADBS range: 0.64-0.78) were low to moderate. Construct validity was acceptable (Comparative Fit Index range: 0.95-0.99). The association between stages and TTM constructs partially followed expected patterns. Suggestions for modifications of TTM measures are discussed for better applicability among proactively recruited samples of individuals with unhealthy alcohol use and with primarily low readiness to change. (PsycINFO Database Record (c) 2013 APA, all rights reserved).