StudiCare procrastination - Randomized controlled non-inferiority trial of a persuasive design-optimized internet- and mobile-based intervention with digital coach targeting procrastination in college students

BACKGROUND: Academic procrastination is widespread among college students. Procrastination is strongly negatively correlated with psychological well-being, thus early interventions are needed. Internet- and mobile-based cognitive behavioral therapy (iCBT) could provide a low-threshold treatment option. Human guidance seems to be a decisive mechanism of change in iCBT. Persuasive design optimization of iCBT and guidance by a digital coach might represent a resource-saving alternative. The study evaluated the non-inferiority of a digital coach in comparison to human guidance with regard to the primary outcome procrastination. METHODS: The iCBT StudiCare procrastination was optimized by principles of the Persuasive System Design (PSD). A total of 233 college students were randomly assigned to either StudiCare procrastination guided by a digital coach (intervention group, IG) or by a human eCoach (control group, CG). All participants were assessed at baseline, 4-, 8- and 12-weeks post-randomization. Symptom change and between-group differences were assessed with latent growth curve models and supported by effect size levels. The non-inferiority margin was set at Cohen’s d = − 0.3. RESULTS: The primary outcome procrastination measured by the Irrational Procrastination scale (IPS) significantly decreased across groups (γ = − 0.79, p < .001, Cohen’s d = -0.43 to -0.89) from baseline to 12-weeks post-randomization. There were no significant differences between groups (γ = -0.03, p = .84, Cohen’s d = -0.03 to 0.08). Regarding symptoms of depression, no significant time x group effect was found (γ = 0.26, p = .09; Cohen’s d = -0.15 to 0.21). There was also no significant time x group effect on the improvement of symptoms of anxiety (γ = 0.25, p = .09). However, Cohen’s ds were above the non-inferiority margin 8-weeks (Cohen’s d = 0.51) and 12-weeks post-randomization (Cohen’s d = 0.37), preferring the CG. Of the IG, 34% and of the CG, 36% completed 80% of the modules. CONCLUSIONS: The PSD optimized version of StudiCare procrastination is effective in reducing procrastination. The digital coach was not inferior to human guidance. Guidance by a digital coach in iCBT against procrastination for college students could be a resource-saving alternative to human guidance. TRIAL REGISTRATION: The trial was registered at the WHO International Clinical Trials Registry Platform via the German Clinical Trial Register (ID: DRKS00025209, 30/04/2021). SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s40359-023-01312-1.