Fig. 2

Causal diagram illustrating how confounding factors (dashed lines) could interfere with the assumed causal relationship between intervention and outcome (solid line) and complicate the interpretation of measured outcomes. Scenario A describes how confounding factors in the treatment setting have increased the risk of carnivore attack, and even if the intervention reduces the risk this effect of the intervention is obscured. Scenario B describes how confounding factors in the treatment setting have reduced the risk of carnivore attack prior to implementation of the intervention, and the ineffectiveness of the intervention to further reduce the risk is obscured