FIGURE 5.

Causal directed acyclic graph (DAG) (A) adapted from Hernán³ and corresponding single-world intervention graphs (SWIGs) for the example in Greenland.¹¹ The box around $X$ in SWIG (B) represents conditioning on $X$ when checking the cohort condition, and the box around $D$ in SWIG (C) represents conditioning on $D$ when checking the case–control condition.