The incidence rate is the number of new cases of a disease in the total population per unit time.
incidence rate =
= ((A) / (a + b + c + d)) / T)
where:
• A = number of new cases of a disease for given time period, which is a subset of all the true positives (a + c) ;
• (a + b + c + d) = sum of (true positives, false positives, false negatives, true negatives) = total population
• T = unit of time
