Randomisation
Since it was deemed too difficult and logistically challenging for teachers to ensure that every child played according to an individually randomised gaming condition, we used clustered randomisation to assign the gaming condition by classroom. Therefore, 16 clusters, each containing 10 to 33 children, were semi-randomly assigned to either play the reading version of GraphoGame-NL, a math version of GraphoGame (active controls), or attend the normal school curriculum (passive controls). Where possible, a within-school design was set up: three schools participated with three classrooms, so each of the three gaming conditions was randomly assigned to one of the three classrooms. Another two schools joined with two classrooms, where the reading and math game were randomly assigned to each classroom. The final three schools joined with one classroom and therefore, each school was assigned to one of the three gaming conditions. See 