appraisal constitutes one opportunity for giving feedback on school leader s efforts to assume wider leadership tasks and responsibilities and can be used to point school leaders towards opportunities to engage in activities that may help improve the wider system research has increasingly stressed the benefits of using multiple tools to form a fair valid and reliable picture of a school leader s performance from a comprehensive perspective however school leaders and evaluators need to have the necessary capacity and competence to choose suitable instruments and understand fairness reliability and validity concerns