Measuring fluid intelligence on a ratio scale: Evidence from nonverbal classification problems and information entropy

Drawing on the g factor and information theory literatures, the relationship between the four subtests of the Culture-Fair Intelligence Test (CFIT) and the entropy of the Ruiz Absolute Scale of Complexity Management (R-ASCM) was investigated. In results based on data collected from 186 university students, the entropy of the R-ASCM mostly loads the first principal component extracted from the CFIT subtests and shows a corresponding strong relationship with the item difficulty of the R-ASCM. Because entropy is a ratio scale of complexity— with a true zero and units called bits—these findings suggest that entropy is the right vehicle for measuring the information contained in nonverbal intelligence tests.