According to the weak local independence approachto defining dimensionality, the fundamental quantitiesfor determining a test’s dimensional structure are the covariancesof item-pair responses conditioned on examineetrait level. This paper describes threedimensionality...

A new index based on the conditional covariance of item scores given a latent variable is defined and investigated to assess dimensionality in educational and psychological test data. This index successfully detects the test dimensionality in both identifying the number of dimensions present in...