A project to evaluate Furth's Inventory of Piaget's Developmental Tasks is described, particularly as that test might be useful in adapting instruction and curricula to the cognitive level of science students. This multiple-choice paper-pencil inventory has 72 items in five problem areas: conservation, images, relations, classification, and laws. The test was designed to measure both concrete and formal operations for subjects eight years of age and older. This study measured the reliability of the test for groups in third grade, sixth grade, ninth grade, and college. The lowest reliabilities were found in sixth grade, the age closest to the transition from concrete to formal operations. Test validity was studied several ways. Group and individual administrations were found to give similar results. Age trends followed expected patterns. Correlations with test scores and academic grades ranged from .42 to .87. It was concluded that this is a useful test in certain areas, and that it would be valuable to develop norms. The data were not conclusive, but it appeared that this test would also be useful with mildly or moderately retarded adults. (Author/CTM)