Does your team function in an environment where top performers are punished while low performers are rewarded? "Of course not!" you may respond. Before you issue an automatic response you may want to stop and consider how low, high and average performers are treated on your team.
Do top performers get the most complex or difficult work assignments? Are top performers consistently asked to mentor others? Are top performers regarded as "walking policy manuals" and constantly called upon by others to produce information on demand? Is it assumed that top performers can handle any challenge you throw at them? Do any of these practices have a punitive effect?
Do low performers get easier assignments that they can handle without making grave errors or producing problems? Do the most difficult team members get more uninterrupted time than those who are viewed as having expertise simply because they are unpleasant to deal with? Does the team leader simply correct the errors of the low performer instead of teaching the person how to correct their own errors? If any of these conditions exist, low performers are being rewarded for their lack of knowledge, skills, abilities or awareness.
Are average performers allowed to make contributions that don't require strain or stretch on their part? Are average performers given more realistic timelines than top performers? Is average performance accepted as the norm for most team members? If so, mediocrity reaps greater rewards than does exemplary performance in your team.
To mitigate performance risks it is necessary to invert the existing system. Low performers need to be given progressively more complex work, along with close supervision in performing the tasks in order to help them to achieve more. Mediocre performers need to be provided with performance plans that progressively shorten timelines, and require more effort be put forth. Top performers will be rewarded with the occasional plum assignment, and the opportunity to choose whether or not they would like to be responsible for coaching others. If excelling begins becomes more desirable, more team members might decide to take the risk of heightened performance.