RESUMEN
Objective: Previous research indicates positive effects of feedback based on rational or empirical decision rules in psychotherapy. The implementation of these usually session-to-session-based feedback systems into clinical practice, however, remains challenging. This study aims to evaluate decision rules based on routine outcome monitoring with reduced assessment frequency. Method: Data routinely collected every 5-20 sessions of N = 3758 patients treated with CBT in an outpatient clinic (Msessions = 42.8, SD = 15.4) were used to develop feedback decision rules based on the expected treatment response and nearest neighbors approach, the reliable change index, and method of percental improvement. The detection of patients at risk of treatment failure served as primary endpoint. Results: Significantly lower reliable improvement, higher reliable deterioration rates, and smaller effect sizes were found for patients identified at risk of treatment failure by all rules. The nearest neighbors-based approach showed the highest sensitivity regarding the detection of reliably deteriorated cases. Conclusion: Consistent with previous research, the empirical models outperformed the rational rules. Still, the first-time used percental improvement-based rule also showed satisfactory results. Overall, the results point to the potential of basic feedback systems that might be easier to implement in practice than session-to-session based systems.