Exposures and results must first be assessed quantitatively in order to identify any relation.
Then the incident incidence rates are calculated. Such tests are called "frequency assessments of disease."
When calculated, the correlation between exposures and outcomes is then assessed by measuring "association or effect measurements."
Finally, the impact of eliminating an exposure on the outcome is evaluated by calculating "potential impact measurements."
In general, measurements of disease occurrence are needed to generate association tests, and both are needed to achieve impact measurements.
When exposure are harmful the followings formulas are used to measure various outcomes. e.g ADR monitoring, Post Marketing Surveillance
When exposure are protective the followings formulas are used to measure various outcomes. e.g clinical trails, vaccine studies