Fig. 1.

Flowchart. Note: The inclusion and exclusion criteria¹ for the target population were as follows: Belonged to the larger longitudinal study basic group; had written consent for participating in the intervention; was a native Finnish speaker; and had previous data concerning reading and math skills and achievement scores from grades 6 and 7. Randomization² was conducted in two phases: First, an equal number of male and female adolescents with poor academic skills were identified. Second, an equal number of same-sex classmates who had normally developed academic skills were randomized into the study. All participants were randomly allocated into three study conditions by an independent researcher