The aspects, qualities, or dimensions that distinguish a more meritorious or valuable evaluand from one that is less meritorious or valuable constitute criteria. Criteria are central to any evaluation, whether they are determined at the beginning of the evaluation or emerge during the evaluation process. In most cases, it is possible, using a needs assessment and an analysis of other relevant values, to identify many criteria. However, the open-ended elements of an evaluation often uncover other criteria that should also be considered when drawing conclusions. Performance or attributes are evaluated on each criterion, and the results are then synthesized to draw evaluative conclusions.