Definitions of causation from the epidemiological literature
| Production | Causes are conditions that play essential parts inproducing the occurrence of disease.2 9 |
| Necessary causes | A necessary cause is a condition without which the effect cannot occur. For example, HIV infection is a necessary cause of AIDS.14-22 |
| Sufficient-component causes | A sufficient cause guarantees that its effect will occur; when the cause is present, the effect mustoccur. A sufficient-component cause is made up of a number of components, no one of which is sufficient on its own but which taken together make up a sufficient cause.26 29 |
| Probabilistic cause | A probabilistic cause increases the probability of its effect occuring.1 12 15 19 35-37 Such a cause need not be either necessary or sufficient. |
| Counterfactual causes | A counterfactual cause makes a difference in the outcome (or the probability of the outcome) when it is present, compared with when it is absent, while all else is held constant.46-48 The counterfactual approach also does not specifically require that causes must be necessary or sufficient for their effects. |