Traditionally, the test score represented by the number of items answered correctly was taken as an indicator of the examinee's ability level. Researchers still tend to think that the number-correct score is a way of ordering individuals with respect to the latent trait. The objective of this study is to depict the benefits of using ability…

Latent trait models introduced the concept of the latent trait, or ability, as distinct from the test score. There is a recent tendency to treat the test score as through it were a substitute for ability, largely because the test score is a convenient way to place individuals in order. F. Samejima (1969) has shown that, in general, the amount of…

In latent trait theory the latent space, or space of the hypothetical construct, is usually represented by some unidimensional or multi-dimensional continuum of real numbers. Like the latent space, the item response can either be treated as a discrete variable or as a continuous variable. Latent trait theory relates the item response to the latent…