This 1976 master’s thesis evaluated the effects of a two year after-school chess intervention, with 42 lessons in total, on grade 5-6 Belgian students’ math and reading achievement. The randomly assigned sample was comprised of 20 treatment group students and 17 control group students. All students were male and attended the same school. Using ANOVA, the author found an effect size of 0.280 standard deviation units in math and effect size of 0.410 units in reading. However, the results were not statistically significant suggesting no difference between students in the treatment and control groups. The study was eligible for inclusion in the systematic literature review and categorized as a Tier I study. Random assignment of students creates treatment and control groups that are presumably equal in terms of past achievement and demographic characteristics, making direct comparisons of the groups possible.