Moderator Analyses

Moderation analyses were conducted to test for differences in overall mean effect size based on the following variables: (1) use of performance measures of EF (eg, Wechsler Intelligence Scale for Children) and self-reports or parent proxy–reports (eg, Behavior Rating Inventory of Executive Function) and (2) time since transplantation. All studies provided the necessary information regarding assessment type to be included in moderation analyses, but 5 studies (ie, 12 effect sizes) did not report time since transplantation and were, therefore, not included.

Moderation analyses were conducted using a random-effects model with maximum likelihood estimation.³⁴ Contrast coding was used for assessment type and time since transplantation was a continuous moderator.