In this study, a deliberate practice-based approach to therapist training will be compared to theoretical teaching. The main hypothesis is that deliberate practice training will result in a larger improvement in students' observer-rated interpersonal skills. About 200 graduate students from two Danish universities will be randomized into two groups, a) deliberate practice training of non-specific psychotherapeutic skills using role-play and Theravue, an online skill-building system with therapy videos; or b) theoretical teaching. Each condition consists of 15 hours of classroom participation and homework. The study has the potential to transform the training of psychotherapy skills.

Background: Psychology students at universities in Denmark and worldwide only receive little clinical training, even though such training is crucial to psychologists' job performance after graduation. Training non-specific psychotherapeutic skills, such as being empathic and facilitating the therapeutic alliance, is critical since these skills are related to psychotherapy outcomes. In this study, a deliberate practice approach to training will be compared to theoretical teaching.

Hypothesis: The first and main hypothesis is that the students' observer-rated Facilitative Interpersonal Skills (FIS) will improve significantly more after deliberate practice training compared to theoretical teaching. The second hypothesis is that students' self-reported Facilitative Interpersonal Skills (FIS-SR), self-efficacy, and empathy will increase significantly more after training compared to theoretical teaching. The third hypothesis is that students reporting higher baseline levels of self-affiliation, attachment security, external feedback propensity, and self-efficacy will have a larger increase in FIS after the training program. The fourth hypothesis is that the amount of deliberate practice will predict improvement in FIS at post-training, whereas the students' sociodemographic characteristics, previous experience with psychotherapy, and preferred psychotherapy approach will not be associated with improvement in FIS.

Methods: One hundred ninety-eight graduate students from the Universities of Copenhagen and Aalborg University will be randomized into two groups, a) deliberate practice training of non-specific skills using role-play and Theravue, or b) theoretical teaching. Group a will first receive the experimental condition (deliberate practice), followed by the control condition, while group b will receive the conditions in reverse order. Each condition consists of 15 hours of classroom participation and homework. The primary outcome is Facilitative Interpersonal Skills - Observer. Secondary outcomes include the Facilitative Interpersonal Skills-Self-Report, the Counselor Activity Self-Efficacy Scales, and the Interpersonal Reactivity Index. Outcomes will be measured at baseline (week 0), after the first condition (week 5; before the crossover, reflecting true randomization), and after both conditions (week 10). Main outcome analyses will be performed at week 5.

To test deliberate practice as a predictor of FIS improvement, the amount of deliberate practice activity is measured on a self-report questionnaire developed for this study and tracked on Theravue as a) the total time spent on watching and responding to therapy videos and b) the average number of attempts to improve the response to each therapy video. The Structural Analysis of Social Behavior Intrex questionnaire (SASB; Benjamin, 2000), the Social Skills Inventory (SSI; Riggio, 1989), the Experiences in Close Relationships Scale (ECR; Brennan et al., 1998), and the Internal and External Feedback Propensity Scales (IEFPS; Herold et al., 1996) will be measured at week 0 and explored as possible between-condition moderators of the outcome. The Group Climate Questionnaire-Short Form (GCQ-S; MacKenzie, 1983) will be used to measure the collaboration in the student groups, where approximately five students work together throughout the study period, performing role-plays and giving peer feedback in the experimental condition, and discussing theory in the control condition. The observer-rated DP Coach Competency Scale (DPCCS; Rousmaniere, 2020) will be used to evaluate adherence and quality of the deliberate practice training. Stig Bernt Poulsen, University of Copenhagen, and Ole Karkov Østergård, Aalborg University, are co-principal investigators.

Discussion: The study can potentially transform the training of psychotherapy, not only for psychology students but also for psychologists in general. Furthermore, the results of the study can be transferred to the training of other clinical skills.

Ethics: Ethical approval has been obtained from the Institutional Ethical Review Board, Department of Psychology, University of Copenhagen, and Aalborg University. Before signing up for the course, the students will be informed about the course and the research embedded herein. Informed consent will be obtained from students agreeing to participate in the study. Course participants can decline to participate in the study without negative consequences for their course participation.

Inclusion Criteria:

• Graduate psychology students attending a 30-hour elective course in clinical psychology called "Deliberate practice training of general psychotherapeutic skills" at two universities in Denmark (i.e., Department of Communication and Psychology at Aalborg University and the Department of Psychology at the University of Copenhagen).
• All participants hold a Bachelor of Science in psychology.
• Signed informed consent.

Exclusion Criteria:

• Course participants who are declining to participate in the study.

The blinding of raters will be ensured for the primary performance-based outcome (i.e., Facilitative Interpersonal Skills) by assigning the video-recorded responses randomly to the raters and concealing the group allocation (experimental vs. control) and time of measurement (week 0, 5, or 10). Furthermore, analyses of outcomes and the conclusion regarding hypotheses 1 and 2 will be performed blinded to allocation (i.e., results in favor of condition X or Y).