A vitality curve is a performance management practice that calls for individuals to be ranked or rated against their coworkers. It is also called stack ranking, forced ranking, and rank and yank.The advantages of the individual ranking method are it is easy to understand and use, it is easy to compare job performance, and it saves money and time. The disadvantages of the individual ranking method are it is not easy to practically compare each of the employees and for large organizations, it is not applicable. The vitality curve creates incentive for employees involved in hiring of peers to avoid the best candidates. ... This may result in hiring lower-caliber candidates than the “C” employees they are replacing, thus actually bringing the overall quality of resources at the organization down.
It creates competition that's needed.