Managing employee performance is a critical role for all leaders, of any group, even volunteers and family members. Expected outcomes depend on the leader's ability to set clear performance expectations (outcomes) and in some situations help by defining methods or processes that are to be used.
Regardless of skill, hiring a person who is a bad fit is wrong decision. In fact, traditional interviewing predicts future success by only 10%. With a bad fit, the employee is never going to reach optimum performance, be fully engaged, and they are likely to leave.