The 5 principles of epidemiology are:
- The health event, condition, or risk factor must be measurable.
- The frequency of the event, condition, or risk factor must be measurable in the population.
- The event, condition, or risk factor must be linked to a specific population.
- There must be a temporal relationship between the event, condition, or risk factor and the disease or outcome.
- The relationship between the event, condition, or risk factor and the disease or outcome must be causal.