Numerous studies have already examined the effectiveness of coaching, but can we determine that it is effective? And what happens when only randomized controlled trials (RCTs) are examined—considered the most rigorous research design for evaluating the effectiveness of interventions?
This study sought to evaluate the effectiveness of coaching through a meta-analysis based exclusively on randomized controlled trials. The researchers analyzed 37 studies comprising 39 independent samples and 2,528 participants, conducted between 1994 and 2021. The studies examined workplace coaching and executive coaching programs and evaluated their effects on personal and leadership-related outcomes.
The findings showed that participants who received coaching achieved better outcomes than the control groups across the range of personal and leadership-related outcomes examined. The overall effect size was positive, statistically significant, and moderate in magnitude (Hedges’ g = 0.59). In other words, even when the analysis was restricted to randomized controlled trials only, the findings supported the effectiveness of coaching in relation to the personal and leadership-related outcomes examined.
Larger effects were found when outcomes were based on participants’ self-reports, compared with measures completed by others. In addition, indications of publication bias were identified, raising the possibility that studies reporting positive findings are more highly represented in the research literature. Therefore, although the overall finding supports the effectiveness of coaching, the researchers emphasize that the magnitude of the effect should be interpreted with caution.
The researchers conclude that the findings of the meta-analysis support the effectiveness of coaching across a range of personal and leadership-related outcomes. The study’s main contribution is that, unlike previous meta-analyses that included a variety of research designs, it was based only on randomized controlled trials and therefore provided a more rigorous assessment of the evidence. However, they emphasize the need for further studies that use measures not based solely on participants’ self-reports, examine more precisely the variables influencing coaching outcomes, and address the risk of publication bias.
Citation:
de Haan, Erik, and Viktor O. Nilsson. 2023. “What Can We Know about the Effectiveness of Coaching? A Meta-Analysis Based Only on Randomized Controlled Trials.” Academy of Management Learning & Education 22 (4): 641–661.