Relative risk is a ratio of the probabil"Relative risk is a ratio of the probability of an event occurring in the exposed group versus the probability of the event occurring in the non-exposed group. For example, the relative risk of developing lung cancer (event) in smokers (exposed group) versus nonsmokers (non-exposed group) would be the probability of developing lung cancer for smokers divided by the probability of developing lung cancer for nonsmokers. The relative risk does not provide any information about the absolute risk of the event occurring, but rather the higher or lower likelihood of the event in the exposure versus the non-exposure group" (Andrade, 2015, and Simon, 2001, as cited in Tenny & Hoffman, 2020). Relative Risk = (Probability of event in exposed group) / (Probability of event in non-exposed group) The example below is to help clarify this formula. "If we hypothetically find that 17% of smokers develop lung cancer and 1% of nonsmokers develop lung cancer, then we can calculate the relative risk of lung cancer in smokers versus nonsmokers as: Relative Risk = 17% / 1% = 17 Thus, smokers are 17 times more likely to develop lung cancer than nonsmokers" (Tenny & Hoffman, 2020).ity