**4. Discussion**

#### *4.1. Overview of Key Findings*

This study sought to examine the evidence base for the association between child development assessment tools and longer-term outcome. After applying a rigorous set of inclusion criteria on 597 studies identified from our initial search, we retained 11 observational cohort studies in this systematic review that investigated the association between a child development assessment tool of interest and a long-term outcome of interest. Although the studies were distributed across all three outcomes of interest, and three development tool domains, the majority of these studies investigated the outcome of academic achievement and used intelligence or neuropsychological/executive function and behavioral tools as predictors. Five of the eleven studies were determined to be high quality and reported measures of association that were almost all significant; given that these studies had at least 100 participants, and a minimum of 5 years duration of follow-up, these would have more statistical power to show a significant effect size. These findings suggest that child development assessment tools across a range of development domains may have predictive potential for various types of outcomes later in life, but several limitations of the available literature and limitations of our study suggest that further research is needed as described below.
