*A study on the effects of coaching found that while training with managers increased manager productivity by 22%, adding one-on-one coaching after the training pushed productivity to 88%.
(Olivero, G., Bane, K.D., and Kopelman, R.E. (Winter,1997). Executive coaching as a transfer of training tool: Effects on productivity in a public agency. Public Personnel Management, 26, 4, 461-469.)