The interpretation of retest scores is problematic because they are potentially affected by measurement and predictive bias, which impact construct validity, and because their size differs as a function of various factors. This paper investigates the construct stability of scores on a figural matrices test and models retest effects at the level of…

This paper describes a computer program in Microsoft BASIC which selects and administers test items from a small item bank. The level of the difficulty of the item selected depends on the test taker's previous response. This adaptive system is based on the Rasch model. The Rasch model uses a unit of measurement based on the logarithm of the…