the effects of coaching

According to a study conducted by the Xerox Corporation, 87 percent of the desired skills change was lost without follow-up coaching. The implication is that no matter how good the classroom training is, the effectiveness is lost without on-the-job reinforcement
Look at the graphic above and you’ll see the effects of coaching. If you have no training or coaching, results are minimal, period. With training, you get better results initially, but they drop off. Where you have training and coaching, you achieve maximum results.

source: http://www.aboutpeople.com/Articles/BusinessCaseforCoaching.php