Order of item difficulty on the WAIS-R picture arrangement subtest: data from a traumatically brain-injured sample

Item difficulty scaling for WAIS-III picture arrangement

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.

Order of item difficulty on picture arrangement: extending the discussion to the WAIS-III

Past examinations of the order of item difficulty on the 10-item WAIS-R Picture Arrangement subtest indicated that the items had not been arranged in increasing order of difficulty. Examination of the clinical data for 50 consecutive assessment referrals [means for age, education, Full Scale IQ, and Picture Arrangement subtest scaled score were 46.4 (SD = 10.2), 12.6 (SD = 1.1), 96.7 (SD = 12.6), and 10.6 (SD = 3.3), respectively] on the 11-item WAIS-III subtest suggested that the current order of items may not be in order of increasing difficulty. Clinical relevance of these findings and research on the order of item difficulty are discussed.