Evaluation operates at several levels: the individual, the school, the local authority and the national. The impact of evaluation at each level depends on the type of information taken into account, the criteria used in judging effectiveness and the action that follows that judgment.When information is derived from summative assessment of pupils carried out for other
purposes, it may not serve the purpose of evaluation. Some of the well-documented disadvantages of schools being judged by whether a specified percentage of pupils reaches a certain level are: