Does the rose still smell as sweet? Item variability across test forms andrevisions

This article examines item stability when the same item appears in differen t contexts. The Ist section considers the assumptions in classical test the ory and item response theory concerning the relationship between the item a nd the trait it is presumed to measure. The 2nd section presents contextual ist challenges to the measurement theory assumptions about item properties and shows the instability of item characteristics across different testing contexts. The 3rd section describes methods for checking the relationship b etween items and traits. Classical test methods, item response methods, and structural equation methods for assessing item stability are reviewed. The instability of item characteristics across contexts should caution researc hers to assess, and not assume, that items operate the same way on differen t test versions. Item instability also indicates the need for a more detail ed understanding of the psychological processes that occur between item and answer.