# Using a Single Measure To Assess Adherence and Differentiation in Family Therapy for Adolescent Externalizing Problems

## TL;DR

This study shows that the TPOCS-RS can measure both adherence to and differentiation from family therapy for adolescents with externalizing problems.

## Contribution

The study provides preliminary evidence that a single measure, TPOCS-RS, can assess both adherence and differentiation in family therapy.

## Key findings

- The TPOCS-RS Family Therapy subscale showed high interrater reliability (ICC = 0.90).
- The TPOCS-RS demonstrated convergent and discriminant validity with treatment integrity and alliance measures.
- The TPOCS-RS identified expected group differences in treatment approaches.

## Abstract

The interpretation of effectiveness research can be enhanced by understanding what prescribed (i.e., adherence) and non-prescribed (i.e., differentiation) techniques were delivered. However, few measures exist that can assess both adherence and differentiation. The current study examined how the Therapy Process Observational Coding System for Child Psychotherapy Revised Strategies Scale (TPOCS-RS) can assess adherence to and differentiation from family therapy for youth with externalizing problems. Treatment sessions (N = 103) from 42 adolescents (M age = 15.0, SD = 1.4; 47.6% female; 59.5% Hispanic/Latinx/e, 19.0% Black, 11.9% multiracial, 4.8% other race) with primary externalizing problems treated by 24 clinicians (M age = 33.2, SD = 8.3; 66.7% female; 33.3% Hispanic/Latinx/e, 20.8% White, 12.5% Asian, 8.3% multiracial, 8.3% other race) in routine practice settings were coded with the TPOCS-RS. Treatment sessions were from three groups: (a) routine family therapy, (b) routine family therapy plus the medication integration protocol, or (c) usual care. Interrater reliability for the TPOCS-RS Family Therapy subscale was ICC = 0.90, and scores demonstrated evidence of convergent and discriminant validity via associations with treatment integrity and alliance measures. The TPOCS-RS Family Therapy subscale also demonstrated evidence of discriminative validity by identifying expected group differences. Results provide preliminary evidence that the TPOCS-RS can measure adherence to and differentiation from family therapy.

The online version contains supplementary material available at 10.1007/s10488-025-01445-y.