Marianne Welmers

Chapter 2 60 Future research on alliance in family-involved treatment could also benefit from investigating the more complex systemic and dynamic aspects of alliance typical of working with families. One of these systemic aspects is the occurrence of split alliances. As pointed out before, the scarce research on split alliances that is available often lacks a clear definition of the concept, and applied methodology in most of these studies might not be appropriate for investigating the role of split alliances in treatment effectiveness. For research on split alliances, applying methods other than using discrepancy scores is recommended, such as multilevel modeling (Bartle-Haring et al., 2012) or polynomial regression (Laird & De Los Reyes, 2013). Furthermore, the use of alliance measures designed specifically for the context of family therapy, such as FTAS (Pinsof et al., 2008) or SOFTA (Friedlander et al., 2006), may help to gain a better understanding of systemic dynamics of alliance in family-involved treatment related to outcome. Although it has been reasoned before that clarifying these systemic dimensions of alliance may help to produce a more accurate estimate of the association between alliance processes and treatment outcome (Friedlander et al, 2006; McLeod, 2011), the present study shows that research investigating the within-family or family- therapist alliance is still scarce. Our findings furthermore indicate that research on the role of alliance in family-involved interventions in treatment effectiveness could benefit from viewing the alliance as a dynamic process rather than a static measure at a single time point. However, research on the evolvement of alliance during treatment is still scarce, and questions remain in particular about the relation between specific developmental trajectories of alliance, such as alliance ruptures or sudden alliance gains, and treatment outcome. Lastly, research on family-involved treatment might benefit from investigating the role of other common factors that have been hypothesized to be important in determining treatment outcome, such as client motivation, expectancies about services and family empowerment (Hoagwood, 2005; Karver et al., 2006; Sprenkle & Blow, 2004). Conclusions We investigated the association between alliance and treatment outcome in family- involved treatment for youth problems by analyzing data from 28 studies reporting on 21 independent study samples. Our findings demonstrate that a stronger alliance is a small but significant predictor of better treatment outcomes, underlining the importance for therapists to develop strong alliances with family members during treatment. The