Which of the following is a Hill's Criteria for causality?

• A. Randomization
• B. Prevalence
• C. Temporality
• D. Specificity of association

Answer: (C)

Temporality is the essential idea here: for something to be causal, the exposure or stimulus must occur before the outcome. In Hill’s considerations for causation, establishing that the cause precedes the effect is what rules out reverse causation and supports a causal interpretation. Without this correct temporal sequence, you can’t claim that the exposure caused the outcome; you might be seeing the result of the outcome or a coincidental association.

The other options don’t address this sequencing. Randomization relates to study design and helps reduce bias, but it isn’t a Hill criterion itself. Prevalence measures how common a disease is at a point in time or over a period, which is about frequency, not causation. Specificity of association is one of Hill’s criteria, but it’s not universally applicable and not the best signal of causality in many conditions where a single factor isn’t responsible for a unique outcome.