Changes in the Utilization in a Flexible and Integrated Model Project for Child and Adolescent Psychiatry in GermanyAbstract: Objectives: We tested hypotheses regarding patients in a flexible and integrative care model of a Child and Adolescent Psychiatry unit offering intensive treatment in an outpatient setting (TIBAS) (intervention group, IG) compared to a control group (CG): reduction in inpatient/daycare treatment and length of stay, increase in outpatient care in hospital, lower readmission and emergency admission rates. Method: We included patients treated between 2018 and 2021 based on routine data from the statutory health insurance system. We formed matched comparison groups from structurally similar control clinics using propensity score matching. The comparison of the IG and the CG referred to the year before and after study inclusion. Results: We analyzed data from a total of 1,806 children and adolescents. The evaluation points towards a strengthening of outpatient care in the IG. However, we found no reduction in the duration of inpatient or daycare treatment nor in the length of stay in the IG compared to the CG across all diagnoses, nor did we determine a decrease in readmission or emergency admission rates. Conclusions: The results indicate an intensification of outpatient care in the model hospital, without evidence of its effects on inpatient utilization. Evaluations of patient-related outcomes of the model project with a comparison group will follow.