Evaluation errors may be unintentional, caused by incompetence, or intentional caused by mendacity. This report is concerned, not with incompetence, but with the production of educational assessments flawed by an evaluator's deceit. The purposes of the paper are: (1) to identify conditions under which people purposely distort evaluation reports, (2) to describe common techniques they use to accomplish their aims, and (3) to suggest a kind of instruction that may help prevent, or at least help uncover, the intentional falsification of educational evaluations. The observations are based on cases gathered through discussions with people engaged in educational research and development, cases appearing in the professional literature, and the author's experience in evaluation activities in the United States and in Southeast Asia and the Pacific. Circumstances which invite distorted assessments are identified, methods used to falsify assessment results are described, and a type of instruction that may encourage greater honesty is suggested. (BW)