Development and Initial Validation of the Therapist Ambiguity Intolerance Scale: Evidence Based on Multilevel Data and Analyses

OBJECTIVE: To facilitate research on therapist factors that relate to treatment implementation and alliance building, the current study developed and validated a scale that measures therapist ambiguity intolerance. METHOD: Using 870 sessions from 257 clients nested within 96 therapists in a Chinese master's training program, the present study developed items for the Therapist Ambiguity Intolerance Scale (TAIS), explored its factor structure, and examined its structural and criterion validities. The analyses were conducted based on a multilevel framework. RESULTS: The results supported a unidimensional structure at the between-client level. Although technically a bifactor model with three specific factors was favored at the within-client level, the results revealed a dominant general factor. The score of the TAIS was positively associated with therapist anxiety and negatively associated with therapist self-efficacy at both the within- and between-client levels. The TAIS score was negatively associated with client-rated working alliance at the between-client level. Additionally, the TAIS score was negatively associated with client-rated session quality at both the within- and between-client levels. CONCLUSIONS: This study offers a useful measure of therapist ambiguity intolerance for research and practice on therapy and training. It highlights the importance of handling inevitable ambiguity in therapy.