Deviations from Perfect Scaling As a Path to Perfect Scaling: An Intelligence Test Example

In our study, we applied State Trace Analysis (STA) to analyze the unidimensionality of an intelligence test (CFT 1-R) and suggest studying violations of unidimensionality at the individual level (Guttman scaling). In a sample of 363 children, a specific item pair was identified that is not unidimensional.