The relationship between the WAIS-III digit symbol Coding and executive functioning

The current study examined the performance of college students (N = 63) on the Coding subtest of the Wechsler Adult Intelligence Scale-Third Edition and examined whether differences in performance could in part be explained by performance on the Delis-Kaplan Executive Functions System Trail-Making Test. The results of a multiple regression analysis indicated that performance on Coding was correlated most with Letter-Number Sequencing and to a lesser extent with Visual Scanning and with Number Sequencing approaching significance. There was no significant relationship with Letter Sequencing or Motor Speed. The three significant predictor variables were then entered into a stepwise hierarchical regression analysis. Subsequent models using Visual Scanning and Number Sequencing did not improve the predictive value of the model. These results are consistent with other recent reports suggesting that performance on Coding taps cognitive skills and abilities beyond that of simple motor speed or paired-associative learning. The findings also suggest a limited improvement in understanding test performance using a process analysis approach.