Materials evaluation involves systematically appraising the potential value of materials for learners based on their objectives. There are two main purposes of materials evaluation - selecting coursebooks and determining effectiveness. Evaluation can occur before, during, or after use of materials. Pre-use evaluation makes predictions about value, in-use evaluates materials as they are being used, and post-use measures actual effects on learners. Evaluation methods include reviews, surveys, checklists, questionnaires, and scales.