Data analysis
Scores were normally distributed to the groups, as assessed by the Shapiro-Wilk normality (p>0.05). There was homogeneity of variances, as assessed by Levene’s test of homogeneity of variance (p>0.05). Scores of children while on methylphenidate and not on methylphenidate were compared using a repeated measures ANOVA. Sequence was a between-subjects effect and interaction betwen medication status and sequence tested whether the effect of being on or off medication differed by sequence of the two conditions. Effect-size calculations using a partial eta squared indicated the magnitude of the difference between the children when medicated or not medicated, taking sequence into account. All analyses were performed with SPSS 20.0