By Elizabeth Ahmann, ScD, RN, ACC, Research Committee.

A study recently published in the Journal of Positive Psychology examined the important question: “Does coaching work?” (Theeboom, Beersma & van Vianen, 2014).

In this study, Theeboom and colleagues conducted a “meta-analysis” of the impact of coaching in organizations. A meta-analysis is a type of research that examines a large number of studies on a specific topic, and their findings, compares, contrasts, and combines evidence from these studies, drawing conclusions that can have several advantages over conclusions from the individual studies themselves. Advantages include the fact that findings from a meta-analysis can often be generalized to a broader population; the statistical power to detect an outcome effect may be increased; and inconsistencies, possible bias, and moderating factors can typically be better examined.

Conducting a meta-analysis requires a decent-sized body of literature on a topic, something coaching research has now accumulated in relation to coaching in organizations. So, this study marks an important milestone for the coaching profession! (Note: A meta-analysis is not yet possible in regard to ADHD coaching due to the limited number of studies in this specific area.)

In this study, Theeboom and colleagues (2014) screened 107 studies of coaching for inclusion in the meta-analysis: 69 were rejected for lack of rigor; 20 others were rejected for definitions of coaching inconsistent with that chosen for the meta-analysis; and, in the end, 18 studies were retained for inclusion.

To examine coaching outcomes, the authors defined “impact of coaching” as “whether coaching has an effect on five both theoretically and practically relevant individual-level outcome categories: performance/skills, well-being, coping, work attitudes, and goal-directed self-regulation” (Theeboom, et al., 2014, p. 1), outcomes that are certainly of interest in ADHD coaching as well.

So: does coaching work? This meta-analysis found significant positive effects on each of the five coaching impact outcomes examined, suggesting, as a result, that “… coaching is, overall, an effective intervention in organizations” (Theeboom, et al., 2014, p. 1). That’s good news for the profession, as well as for individual coaching clients!


Theeboom, T, Beersma, B. & van Vianen, A.E.M. (2014). Does coaching work? A meta-analysis on the effects of coaching on individual level outcomes in an organizational context. The Journal of Positive Psychology, 9(10), 1-18.
DOI: 10.1080/17439760.2013.837499

Liz-Ahmann2Elizabeth Ahmann, ScD, RN, ACC, is a member of the ACO Research Committee, which writes research reviews as a service to ACO members.
Dr. Ahmann works with clients of all ages to help each individual develop the structures, skills, strategies, and self-talk that best support success! She also teaches tele-classes in mindfulness strategies for ADHD. Contact her at