Developments in Latent Trait Theory: Models, Technical Issues, and Applications

There are many shortcomings of standard testing and measurement technology.' For one, the values of standard item parameters (item difficulty and item discrimination) are not invariant across groups of examinees that differ in ability. This means that standard item statistics are only useful in test construction for examinee populations very similar to the sample of examinees in which the item statistics were obtained. Another shortcoming is that comparisons of examinees on an ability measured by a set of test items comprising a test are limited to situations where examinees are administered the same (or parallel) test items. Finally, standard testing technology provides no basis for determining what a particular examinee might do when confronted with a