Incidence rate is calculated by dividing the number of new cases of a disease by the population at risk during a specific period. The formula is: Incidence Rate = (Number of new cases / Population at risk) x 1000 For example, if there were 50 new cases of a particular infection in a hospital with 200 patients over a year, the incidence rate would be: Incidence Rate = (50 / 200) x 1000 = 250 per 1000 patients per year
