The development of a Brief Working Alliance Inventory for clients and therapists using multilevel factor analysis and item response theory in the United States and China.

This study aimed to investigate the multilevel factor structure of the therapist and client versions of the 12-item Working Alliance Inventory-Short Revised (WAI; Hatcher & Gillaspy, 2006) in the United States and China, and to create a three-item brief version (WAI-B3) using multilevel factor analysis (M-FA) and multilevel item response theory (M-IRT). We gathered eight data sets from two samples each in United States and China with a total of 21,623 sessions from 376 therapists and 2,455 clients. M-FA results with the first four data sets (two American and two Chinese) suggested that the 12-item WAI across therapist and client versions, and in both United States and China showed a dominant general WA factor with three specific subgroup factors corresponding to the Goal, Task, and Bond items. We then constructed a three-item WAI-B3 by selecting items 11, 10, and 9 through M-IRT, as the best representative of Goal, Task, and Bond subscales, respectively, for both the therapist and client versions in United States and China. With the other four data sets (two American, two Chinese) to test the WAI-B3, we found adequate multilevel reliability, structural validity, and convergent validity with the original 12-item WAI scores. Multilevel measurement invariance tests provided tentative and mixed support for the equivalence of WAI-B3 between the American and Chinese data sets and between therapist and client versions. We recommend that the WAI-B3 be used in routine clinical practice to track therapy process, and that the WAI-B3 be tested with other client and therapist populations and cultures. (PsycInfo Database Record (c) 2023 APA, all rights reserved).