The 10-Item Substance Use Disorder Outcome Scale: Psychometric evaluation

The current study describes the psychometric properties of a scale (entitled "Substance Use Disorder Outcome Scale-10 items" or 10-Item Substance Use Disorder Outcome Scale) designed for longitudinal studies. Sixteen male veterans attending a substance use disorder recovery clinic were studied over a 2-year period. The attending nurse and physician conducted four, 10-Item Substance Use Disorder Outcome Scale scale ratings, each encompassing a 6-month period, for each participant. Analyses involved scale descriptive results, Cronbach alpha scores, effects of deleting the item on Cronbach alpha scores for the remaining items, and item-to-scale correlations across the four periods, plus three exploratory studies. Scale scores showed skewness p ≤ 1.0 and Cronbach alphas of 0.89 to 0.93. Six of 10 items correlated with total scale scores at 3 or 4 rating periods at p ≤ 0.005. Two items showed p ≤ 0.005 correlations only in the first two periods, and two items showed p ≤ 0.005 correlations only in the last two periods. Exploratory analyses revealed some item convergence over time plus non-significant associations with long-standing demographic and clinical variables. Desirable 10-Item Substance Use Disorder Outcome Scale psychometric properties included normal distribution, excellent Cronbach alphas, and high item-to-score correlations, all of which persisted over time.