Abstract
The working alliance is a key element to increase intimate partner violence (IPV) offenders' motivation, adherence to treatment, and active participation in batterer intervention programs (BIPs). The objective of the present study is to assess the psychometric properties and factor structure of the Working Alliance Inventory-Observer Short Version (WAI-O-S) with a sample of IPV offenders. The sample was 140 men convicted for IPV and court-mandated to a community-based BIP. Inter-rater agreement and reliability were evaluated by computing the intraclass correlation coefficient. To test the latent structure a Bayesian confirmatory factor analysis approach was used. To test criterion-related validity, the WAI-O-S factorial scores were correlated to protherapeutic behavior, stage of change and motivation to change. The WAI-O-S showed an adequate reliability. Results from Bayesian confirmatory factor analyses showed two first-order factors (Bond and Agreement), and a second-order factor (General working alliance) explaining the relationship between the first-order factors. Results also support the validity of this instrument. The availability of reliable and valid observational measure of the working alliance provides a useful tool to overcome self-report measurement limitations such as social desirability, deception, and denial among IPV offenders.