General and specific factors of working alliance in parent training: A bifactor exploratory structural equation modelling approach.

The Working Alliance Inventory Short form (WAI-S) comprises 12 items that measure 3 subdomains (goal, task, and bond). In the present study, we evaluated the factor structure of WAI-S in a parent management training (PMT) context, by investigating a series of different factor models, including standard confirmatory factor analyses (CFA) models and more recent alternatives, like the exploratory structural equation model (ESEM), the bifactor-CFA, and the bifactor exploratory structural equation model (B-ESEM). The study sample consisted of 259 Norwegian parents receiving PMT - the Oregon model (PMTO). Alliance was rated by parents of children with emerging or present conduct problems after the first therapy session. Results showed that the B-ESEM model provided best model fit to the data. Estimated sources of variance and omega reliabilities supported a strong general alliance factor, but revealed poor quality of the specific factors. Overall, the present study implies that specific factors of working alliance should be interpreted with caution; rather one should rely on a general working alliance construct. Clinical or methodological significance of this article: Findings suggest that working alliance, as measured by WAI-S in a PMT context, is best reflected by a general construct that also take into account multidimensionality. However, only the general factors provide acceptable reliability. Consequently, practitioners should use the specific factors with caution. The indicators of the specific factors should be improved.