Study of underlying structure of the WISC-IV using multidimensional scaling and factor analysis methods

Aim: This study was aimed at investigating the basic structure of WISC-IV using Multidimensional Scaling and Confirmatory Factor Analysis and comparing the results to the assumed model.
Design of the study was correlational. Out of 1314 male students studying at 6th distinct of Tehran, 200 were sampled using cluster sampling method. Wechsler intelligence test for children- Fourth edition was used to assess intelligence. Gathered data were analyzed using multidimensional scaling and confirmatory factor analysis.
MDS resulted in 3 separate dimensions (processing speed, presentation mode and response mode) (Stress = 0.021, P = 0.04). 4-factorial model was not admissible (χ2 = 102.63, P = 0.04). However, fit indices of Second-Order Confirmatory Factor Analysis along with some modifications confirmed the 3-factorial model (χ2 = 99.00, P = 0.055).
According to the results WISC-IV scores could be better understood using 3 factorial solution rather than the existing 4-factorial structure so it is suggested that 3-factorial solution could be used in clinical context and for counseling purposes.