Stability of WISC-IV Process Scores

Forty-three students were administered on two occasions approximately 11 months apart the complete Wechsler Intelligence Scale for Children-Fourth Edition, including the seven process components of Block Design No Time Bonus, Digit Span Forward (DSF), Digit Span Backward (DSB), Cancellation Random (CAR), Cancellation Structured (CAS), Longest Digit Span Forward (LDSF), and Longest Digit Span Backward (LDSB). Mean ages at first and second testing were 7.77 years (SD = 1.91) and 8.74 years (SD = 1.93), respectively. Mean Full-Scale IQ at initial testing was 111.63 (SD = 10.71). Process score stability coefficients ranged from .75 on DSF to .32 on CAS. Discrepancy score stabilities ranged from .45 on DSF minus DSB to .05 on CAS minus CAR. Approximately 21% of participants increased their LDSF on retest, and 16.3% showed a gain on LDSB. Caution must be exercised when interpreting process scores, and interpretation of discrepancy scores should probably be avoided.