High Quality Content by WIKIPEDIA articles! Evaluation approaches are conceptually distinct ways of thinking about, designing and conducting evaluation efforts. Many of the evaluation approaches in use today make unique contributions to solving important problems, while others refine existing approaches in some way. Classification systems intended to sort out unique approaches from variations on a theme are presented here to help identify some basic schools of thought for conducting an evaluation. After these approaches are identified, they are summarized in terms of a few important attributes.