The most difficult criterion to establish Causal association in etiology of a disease is-: (A) Temporality, (B) Strength of association, (C) Specificity of association, (D) Biological plausibility
Answer is C. Specificity of association means that the disease is caused by a paicular risk factor. It is difficult criterion to establish, as it is difficult to rule out the same outcomes by other exposures. Other Hill's criteria of causal association/ Surgeon general's criteria include: Temporality Consistency Strength Biological plausibility Coherence Dose response relationship Cessation of exposure.