In reply to Jeff Walter.

From http://www.scrumalliance.org/articles/50

"W. Edwards Deming identified performance appraisal as one of the Seven Deadly Diseases of Management. Deming is clear and concise in stating the negative effects of performance appraisals and merit ratings: “It nourishes short-term performance, annihilates long-term planning, builds fear, demolishes teamwork, nourishes rivalry and politics.” [Deming p. 102]

More recently, Stanford University professors Robert Sutton and Jeffrey Pfeffer combed through data and studies related to widespread management practices. They reference a survey of 200 human resource professionals which reports that forced ranking—a common component of performance appraisal programs—results in “lower productivity, inequity and skepticism, negative effects on employee engagement, reduced collaboration, and damage to morale and mistrust of leadership.” [Pfeffer and Sutton, p. 107] They go on to describe the damage done by merit pay plans.

In short, the evidence supporting the benefits of rating, ranking, and then tying pay to the rating—the stuff of performance evaluations—is thin to none. Deming had it right."