Compared on classificatory ability were the performances of children in grades 2-4 who had been exposed to the Science Curriculum Improvement Study (SCIS) program for two years and children who had not. No significant differences in performance either quantitatively or qualitatively were detected. It was concluded that the grouping and classificatory exercises provided by the SCIS program were redundant, and it was suggested that practice be offered in hierarchical reclassification and the transfer of classificatory skills. (GR)