A Study of Equating in NAEP
This study investigates the amount of uncertainty added to NAEP estimates by equating error under both ideal and less than ideal circumstances. For example, circumstances led to a situation in which the 1994 to 1992 reading assessment equating had to be based on a set of common items that was both smaller, and more heavily weighted toward multiple choice, than anticipated. If performance on the two types of items does not change at the same rate over time, such equatings might introduce systematic bias in trends measured from equated scores. Data from past administrations are used to guide simulations of various (better and worse) equating designs, and error due to equating is estimated empirically.