Standardized tests are widely used in intellectual disability research, either as dependent or control variables. Yet, it is not certain that their items give rise to the same performance in various groups under study. In the present work, 48 participants with Down syndrome were matched on their raw score on Raven's Colored Progressive Matrices…

Raven's Coloured Progressive Matrices (RCPM) is a standardised test that is commonly used to obtain a non-verbal reasoning score for children. As the RCPM involves the matching of a target to a pattern it is also considered to be a visuo-spatial perception task. RCPM is therefore frequently used in studies in Williams Syndrome (WS), in order to…

Where estimation of abilities in the lower half of the ability distribution for the Raven Progressive Matrices is important, or an increase in accuracy of ability estimation is needed, the multiple category latent trait estimation provides a rational procedure for realizing gains in accuracy from the use of information in wrong responses.…