COMPARISON OF ERROR RATES AND PERFORMANCE ON WECHSLER CODING AND DIGIT SYMBOL SUBTESTS AND THE SYMBOL-SYMBOL TEST FOR CHILDREN AND ADULTS

Performance on Digit Symbol, Coding, and similar symbol-substitution t ests are known to be influenced by a wide variety of reversible and no nreversible organic syndromes and learning disabilities. Recently, que stions regarding the interchangeability of different symbol-substituti on tests have been raised. The present study compared the performance, i.e., number of substitutions completed accurately and number of erro rs, of 37 adults, 32 adolescents, and 45 children on the Wechsler symb ol-substitution tests of Digit Symbol and Coding with their performanc e on the recently designed Symbol-Symbol test. Analysis indicated that , while Symbol-Symbol performance is highly correlated with Wechsler s cores on symbol-substitution tests, significant differences in error r ates and speed of performance suggest that the Symbol-Symbol test cann ot be considered an equivalent symbol-substitution test. Further inves tigation of the properties and the potential uses of the Symbol-Symbol test with clinical populations must be undertaken.