Published in 2007, this study evaluated the effects of a one year, in-school chess program on cognitive development. Taking place in Seoul, South Korea, 18 students were randomly assigned to a treatment group and 20 students to the control group. Chess students received 12 weekly lessons for one academic year. The program targeted students with special education needs. Students ages 8-12 completed pre- and post-tests for Raven’s Progressive Matrices Test (RPM) and the Test of Nonverbal Intelligence (TONI-3). The pre-test scores for treatment and control students on the TONI-3 and RPM did not significantly differ. Using a 2X2 factorial ANOVA design, the authors found an effect size for the impact of chess on cognitive outcome measures of 0.172 standard deviation units. However, the results were statistically insignificant suggesting no difference between treatment and control students. The study was eligible for inclusion in the systematic literature review and categorized as Tier I since it used random assignment. However, the small sample size and sample composition of special education students limits the generalizability of the results to other student populations.