The association between therapeutic alliance and outcome in internet-based psychological interventions: A meta-analysis

Background: Internet-based psychological interventions have proven effective and yield advantages that make them a viable alternative to face-to-face therapy in many fields. Yet, the role of therapeutic alliance in technologically mediated interventions has been discussed critically. The aim of this meta-analysis is to summarize the association between therapeutic alliance and outcome in therapist-assisted online interventions. Methods: A systematic search of the databases PubMed, Web of Science, PsycINFO and PubPsych was conducted for articles published before February 2020 that assess the association between therapeutic alliance and outcome in internet-based interventions involving remote therapist contact. Results were systematically screened and information on the alliance-outcome-association was extracted. A multilevel meta-analysis was conducted. Results: Overall, 51 effect sizes were extracted from 20 included studies. The average weighted effect size is r = 0.203 (p <.0001). The correlation was larger when alliance was measured near the end of an intervention. There was no impact of therapist contact frequency or mode and availability of self-help content on the effect size. Conclusions: Therapeutic alliance and outcome are significantly correlated in internet-based therapy. This points to the relevance of a stable alliance in internet-based interventions and suggests that fostering alliance might be beneficial to treatment success.