Development of a short form of the Treatment Evaluation Inventory for acceptability of psychological interventions.

The Treatment Evaluation Inventory of Kazdin, French, and Sherick is a 19-item measure of the perceived acceptability of behavioural treatments. Development of two brief forms was based on data from two sources. For Study 1, data from 218 completed questionnaires were used to develop internally consistent brief scales. In Study 2 internal consistency and the validity of the brief forms were estimated for a set of 131 questionnaires. Item reduction was achieved by analysis of item-total minus item correlations. Brief forms with 3, 6, 9, and 12 items were proposed. Their internal consistency (Cronbach alpha) and construct validity were based on correlations of scores on each short form with the full scale scores and on comparing means of different forms. Discriminant validity was based on the difference between two groups (estimated effect size 0.7). Scores for all forms showed high internal consistency and correlated highly with total scale scores. Only the 12-item brief scale yielded mean scores similar to the full scale. The 3-item form could be used as a quick screen, and the 12-item form for more intensive purposes as it is most similar to the full-scale.