 The content areas of the tests are based on the National Assessment of Educational Progress (NAEP) fourth-grade content areas, adapted to be age appropriate at each grade level.The assessments were scored using a three-parameter Item Response Theory (IRT) model.Reardon and Galindo (2009) found that average Hispanic and black students begin kindergarten with math scores three quarters of a standard deviation lower than those of white students and with reading scores a half standard deviation lower than those of white students.