DEFINITION: Consistency and dependability of data collected through repeated use of a scientific instrument or data collection procedure under the same conditions.
COMMENT: Absolute reliability of evaluation data is hard to obtain. However, checklists and training of evaluators can improve both data reliability and validity. Sound reliability implies exhaustive data collection and the appropriateness of the evaluative questions asked.
SOURCE: Handbook on Monitoring and Evaluating for Results. UNDP, Evaluation Office, NY, 2002.