Fig. 3. Two Scenarios for How Maternal Smoking During Pregnancy Relates to Child Preterm Birth and to Child ADHD.
It is not standard practice to include numeric values corresponding to paths, or differing edge widths in DAGs; however, we do so in Figures 3a-3b for illustrative purposes, to highlight the differing strength of the relationships depicted in the two contrasting scenarios. The magnitude of the value appearing next to an edge, and the width of the edge, both reflect the strength of the (directed) relationship between the two variables connected by the edge, in the model used to generate simulated data consistent with the DAG. (Abbreviations: ADHD = attention-deficit/hyperactivity disorder)