Table 3.
Bradford Hill Guideline | Explanation | Result | |
---|---|---|---|
1 | Strength | numbers large enough not to be chance observation | yes |
2 | Consistency | association observed by different persons, in different places and times | yes |
3 | Specificity | association limited to specific people/areas/effects | yes |
4 | Temporality | effects occur after exposure | yes |
5 | Biological gradient | association has biological gradient or dose-response relationship | yes |
6 | Plausibility | suspected causation fits biological knowledge of the day | no |
7 | Coherence | suspected causation accords with natural history and biology | no |
8 | Experiment/animal studies | other experimental evidence available | not available |
9 | Analogy | similar evidence from other studies | yes |