This investigation was concerned with an evaluation by a panel of psychologists of both the validity and the reliability and measurement error of two tests of critical thinking: (a) the Cornell Critical Thinking Test, Level X and (b) the Watson-Glaser Critical Thinking Appraisal, Form YM. As criteria, the ten ESSENTIAL validity standards and the five ESSENTIAL reliability and measurement error standards from the 1974 publication Standards for Educational and Psychological Tests were employed. For each of the 15 standards used, the respondent rendered a judgment in the instance of each test of critical thinking concerning whether the standard was met completely, somewhat, minimally, or not at all. Corresponding to each of these levels, scores of 4, 3, 2, or 1 were assigned. In the instance that a standard was judged not to be applicable, no score was given. In general, it appeared that both measures tended to meet the standards between a level judged to be "minimal" or "somewhat." No statistically significant difference occurred between the means of the mean ratings assigned to the two scales. It is recommended that the authors of the tests consider making revisions necessary to enhance their reliability and validity.