The current study was designed to extend the current literature to study scale drift in CAT as part of improving quality control and calibration process for ACCUPLACER, a battery of large-scale adaptive placement tests. The study aims to evaluate item parameter drift using empirical data that span four years from the ACCUPLACER Arithmetic assessment. The results suggest that the Arithmetic test maintained a reasonably stable scale in the years 2004 through 2007. The following is appended: Summary Statistics of Item Exposure Rates across Years.