Refined item digraph analysis (RIDA) is a way of studying diagnostic and prescriptive testing. It permits assessment of a test item's diagnostic value by examining the extent to which the item has properties of ideal items. RIDA is illustrated with the Orange Juice Test, which assesses the proportionality concept. (TJH)

Studied effects of students' use of calculators with 2 experimental forms of a university mathematics test taken by 765 and 725 college students, respectively. Calculator effects are not found for overall scores but are seen for some individual items. Analysis at the item level makes the actual impact apparent. (SLD)