Three intensively trained raters (K.L.H., T.E., Michael Singer, BA) coded individual studies. Although effort was made to use exact values, we adopted procedures to optimally approximate moderators when precise values were unavailable (eg, taking midpoints of ranges for ages and years if exact information was not provided). Rater agreement for moderator codes was 92%. When raters provided contradictory judgments, disagreements were discussed and the lead author made a final determination.
