Marianne Welmers

Alliance Discrepancies 105 CHAPTER 4 by informant bias. That is, differences between alliances from family members’ self- reports might be a result of different informants reporting on different alliances (e.g., mother reporting onmother’s alliance, father reporting on father’s alliance, etc.), whereas for therapist- and observer reports different alliances are evaluated by the same person (e.g., therapist reporting on both mother’s and father’s alliance). A final limitation of the study is that the interrater reliability of observer-reports of the alliance was small (ICC = .44), albeit sufficient (Cicchetti, 1994). However, according to Koo and Li (2016) a relatively low ICC score could be explained by low variability among sampled subjects, a small number of subjects ( k < 30) or a small number of raters ( n < 3). They suggest that a reliability study should include at least 30 heterogeneous samples being tested by at least 3 raters before low ICC scores should be interpreted in terms of poor reliability. In our study, we single-coded most sessions, which automatically generates lower agreement as compared to consensus coding by two or three coders. Despite its limitations, our study adds to the body of knowledge on alliance in family treatment in several ways. To our knowledge, it is the first study on alliance in the unruly context of home-based family treatment focusing on multiple alliances with different family members, including observations as well as both therapist-reports and client self- reports. Furthermore, we used a multilevel model to account for statistical dependency, allowing us to compare alliances of different family members regardless of who reported on the alliance, and to compare different perspectives (i.e., therapist, client, observer) on alliance discrepancies. Finally, the use of two different measure moments enabled analyses of the development of alliance discrepancies between family members and of congruence between therapist-reports and client self-reports of the alliance. Future research on alliance in family treatment should focus on investigating the effect of alliance discrepancies between family members as well as the effect of congruence between therapist- and self-reports of the alliance on treatment outcome. Ideally, in this kind of research a developmental approach is applied, as our study findings demonstrate that alliance discrepancies and congruence between therapist-report and client self- report of the alliance evolve during treatment. With regard to alliance discrepancies, previous studies provide some evidence that discrepancies between family members within the family contribute to treatment dropout (Friedlander et al., 2018, Muñiz de la Peña et al., 2009; Robbins et al., 2003; Robbins et al., 2008). However, to date there is only a handful of studies on alliance discrepancies in relation to treatment outcome, with various definitions and often problematic methodologies (Welmers-van de Poll et al., 2018), and none of these studies investigated how the development of alliance discrepancies (i.e., increase or decrease of discrepancies) can affect treatment outcome.