Binet Item Difficulty Then and Now

GARFINKEL, ROBIN, and THORNDIKE, ROBERT L. Binet Item Difficulty Then and Now. CHILD DEVELOPMENT, 1976, 47, 959-965. This study was conducted to determine how items of the Stanford-Binet Intelligence Scale, Form L-M, had performed in the 1930s standardization sample in comparison with the 1972 standardization sample. Curves were fitted to raw percentage passing at successive age levels using a normal maximum-likelihood technique adapted from work done in the area of bioassay. Most items were found to have decreased in difficulty from the 1930s to the 1970s. This was especially true at the younger age levels. A few of the items that became more difficult contained specific content that could be expected to be less familiar to children of the later sample. Items tended to become more age specific in the 1972 sample.