NIFDI's most recent Technical Report, An Analysis of Achievement Scores of Arthur Academy Schools, examines data from the Stanford Achievement Test (SAT) and Oregon Assessment of Knowledge and Skills (OAKS) on the reading and mathematics achievement of Arthur Academy students from six consecutive school years: 2007-2008 through 2012-2013. 

The data indicate that at the start of kindergarten, Arthur students had achievement scores that were similar to or slightly lower than students in the nation as a whole. However, by the end of their kindergarten year, the situation had reversed as the average Arthur student scored much higher than peers in the nation. This high level of achievement persisted, and even increased, through later grades. In all cases, the changes over time were statistically significant, and the percentage of students scoring at high levels was substantially higher than would be expected relative to national norms.

Arthur Academies are a set of six charter elementary schools in the greater Portland, Oregon metropolitan area. All of the Academies use the Direct Instruction programs, Reading Mastery Signature Edition and Connecting Math Concepts.