Factor analysis of breadth and depth dimensions on Wechsler's Similarities and Vocabulary Subscales

Previous research (Bailey, Lazar, & Edinger, 1977) has indicated the presence of Breadth and Depth factors on the Similarities subscale of the WAIS. The present study (N = 102) analyzed these two factors further, by using measures of Breadth and Depth on both the Similarities and Vocabulary subscales. Several other measures also were studied, including a Comprehension index, SAT scores, and GPA. Results of a factor analysis with oblique rotation revealed distinct Breadth and Depth factors, which strongly supported the theoretical rationale of the study. The Breadth factor seems to reflect broad-range skills of the type required on conventional IQ tests, while the Depth factor is less theoretically clear. It is suggested that Depth involves an effort component as well as ability because the S is required to provide more than a single correct answer for a given item.