Which of the following is a Bradford Hill criterion indicating a dose-response relationship?

• A. Temporality
• B. Consistency
• C. Dose-response
• D. Coherence

Answer: (C)

The concept being tested is the dose–response, also called the biologic gradient, criterion. It looks for a pattern where increasing exposure to a factor leads to an increasing effect or risk. When such a graded relationship is observed, it strengthens the case that the exposure might cause the outcome, because a true causal effect often scales with how much exposure occurs rather than staying constant regardless of dose.

For example, if higher levels of a toxin exposure consistently correspond to higher rates of disease, that suggests a causal link rather than a random association. This is why the dose–response pattern is valued in causal inference: it provides a tangible link between the amount of exposure and the magnitude of the effect.

Keep in mind that a dose–response relationship supports—and does not by itself prove—causality. Other Bradford Hill criteria, like temporality, consistency, and coherence, also play important roles in building the overall case.