The test of discriminant validity based on a series of chi-square difference tests
using measures of each pair of constructs provided evidence of such validity. A
two-dimensional model for each pair of constructs was first fit, and then items
representing each construct were forced into a single-factor solution. The chi-square
difference test produced a significant result for each pair of measures. Thus, imposing
a single factor solution on the two sets of items representing different constructs
demonstrated a significant deterioration of the model fit, providing evidence of
discriminant validity (Anderson and Gerbing, 1988).