Northwest Evaluation Association

"Back when NWEA was established in 1977, paper-based testing ruled. So founders Allan Olson, George Ingebo, and Vic Doherty pioneered new ways to measure student growth using an empirically-derived scale based on Danish mathematician Georg Rasch’s Item Response Theory model. Their solution—our NWEA RIT (Rasch Unit) scale—accurately measures student growth term-to-team and year-to-year."