Divisions & Services
Department of Ob/Gyn
Criteria for Causation
"Scientists believe in proof without certainty;
most people believe in certainty without proof." Ashely Montagu
Sir Bradford Hill
established the following nine criteria for causation (does factor A cause disorder B).
Although developed for use in the field of occupational medicine, these criteria can be used in most situations.
- Strength of the association. How large is the effect?
- The consistency of the association.
Has the same association been observed by others, in different populations, using a different method?
- Specificity. Does altering only the cause alter the effect?
- Temporal relationship. Does the cause precede the effect?
- Biological gradient. Is there a dose response?
- Biological plausibility. Does it make sense?
- Coherence. Does the evidence fit with
what is known regarding the natural history and biology of the outcome?
- Experimental evidence. Are there any clinical studies supporting the association?
- Reasoning by analogy. Is the observed association supported by similar associations?
Bradford-Hill A. The environment and disease: Assocation or causation?
Proc R Soc Med 1965;58:295-300.
Grimes DA. Cause and effect - or coincidence?
Contemporary OB/GYN Jan 1984;109-15.
Peterson HB, Kleinbaum DG. Interpreting the literature in Obstetrics and Gynecology:
I. Key concepts in epidemiology and biostatistics. Obstet Gynecol 1991;78(4):710-17.
By Phil Hahn (November 22, 2004), Dept of Obstetrics & Gynaecology, Queen's University