AbstractIn many organizations the measurement of job performance can not rely on easily quantifiable information. In such cases, supervising managers often use subjective performance evaluations. We use laboratory experiments to study whether the way employees are assigned to a manager affects managers’ and co-employees’ subjective evaluations of employees. Employees can either be hired by the manager, explicitly not hired by him and nevertheless assigned to him or exogenously assigned to him. We present data from four different treatments. For all four treatments we find escalation bias by managers. Managers exhibit a positive bias towards those employees they have hired or a negative one towards those they have explicitly not hired. For three treatments we find that managers’ and employees’ biases are connected. Exogenously assigned employees are biased in favor of employees hired by the manager and against those explicitly not hired.