The Question

Executive coaching is a substantial and growing industry. The evidence for its effectiveness has been generally positive, but much of it has come from studies without control groups, making it difficult to establish whether coaching produces outcomes beyond what would have occurred anyway. De Haan and Nilsson (2023) restricted their meta-analysis to randomised controlled trials only, the strongest available design for causal inference.

What They Found

Across 37 RCT studies of workplace and executive coaching conducted between 1994 and 2021, involving 39 coaching samples and 2,528 total participants, the analysis found a statistically significant effect of workplace coaching across all leadership and personal outcomes. The best estimate of the standard effect size was g = .59, falling within the moderate range (de Haan & Nilsson, 2023).

There were indications of significant publication bias, as would be expected in a field where negative findings are less likely to be published. The true effect, adjusted for publication bias, is therefore likely somewhat smaller than .59, though the authors judged the evidence for overall coaching effectiveness to be clear and meaningful.

Moderator analyses showed that effects were larger for self-reported than observed outcomes, larger with qualified coaches in non-leadership applications, and somewhat larger with female coachees. The length of the coaching assignment did not substantially affect outcomes (de Haan & Nilsson, 2023).

The Coregulation Model

The authors develop a theoretical model based on coregulation between coach and coachee: the idea that the quality of the coaching relationship and the mutual regulation that occurs within it is the primary mechanism of change. This model was confirmed across the five moderator analyses, with factors that enhance coregulation, such as qualified coaches and self-reported outcomes closer to the coachee’s subjective experience, showing larger effects (de Haan & Nilsson, 2023).

Reference

de Haan, E., & Nilsson, V. O. (2023). What can we know about the effectiveness of coaching? A meta-analysis based only on randomized controlled trials. Academy of Management Learning & Education. Advance online publication. https://doi.org/10.5465/amle.2022.0107