Item difficulty scaling for WAIS-III picture arrangement

Abstract

Only one study regarding the sequencing of items of the WAIS-III Picture Arrangement subtest was located in a search of published literature. That study of 50 alcohol abusers failed to demonstrate that the items are sequenced in the perfect order of difficulty as suggested by the test publisher. The current study was accomplished to replicate or refute the prior study and to extend findings into related matters. Two laboratories provided four archival samples of 100 cases. Only five items appear properly placed, with one (OPENS) especially misplaced. A new sequence is recommended so that clinicians can administer the test more efficiently and examine errors from a process approach to evaluation. Difficult items were not passed as often as expected by Hispanic respondents. This finding was considered an artifact related to archival convenience sampling and may not be representative as a general finding regarding Hispanic performance until experimental sampling techniques or proper statistical controls can be applied. Statistically controlling for IQ, through analysis of covariance, eliminated ethnicity effects on total score for the PA subtest.