Curated summaries of external studies, one entry per source. Each is checked against its source and graded for strength of evidence.
A meta-analysis of 27 samples (3,563 coaching processes) finds a moderate, robust association between working alliance and client outcomes (r = .41), strongest for satisfaction and perceived effectiveness, and a negative association with unintended negative effects (r = −.29).
A systematic review of 110 peer-reviewed executive coaching outcome studies finds more than 70 reported outcomes, mostly from case studies and self-reports, with few studies looking at organizational results or social context.
A meta-analysis of 20 studies (957 participants) of psychologically informed workplace coaching finds g = 0.51 overall, largest for goal attainment (g = 1.29), with no significant difference between coaching approaches.
A meta-analysis of 37 randomized controlled trials (39 samples, n = 2,528) finds coaching improves leadership and personal outcomes, with a best estimate of g = .59, and reports significant publication bias.
A meta-analysis of 11 workplace coaching studies published after 2014 finds g = 0.44 overall, larger for skills than for attitudes, and notes that no included study measured results-level outcomes.
A meta-analysis of 17 workplace coaching studies (2,267 people) finds a positive overall effect (δ = 0.36), larger without multisource feedback and with internal coaches, but the biggest effects come from subgroups of only three studies.