Final answer:
The incidence rate is the measure of new cases of a disease in a population over a certain time, used to assess risk factors and control measures.
Step-by-step explanation:
The incidence rate of a disease refers to the number or proportion of new cases of a disease that appear in a specific population during a certain time period. It is a crucial measure in understanding the risk factors and the spread of disease and is fundamentally different from prevalence, which accounts for both new and existing cases. Incidence rates can be expressed in different ways, such as percentages or as the number of cases per 100,000 individuals, to make the statistics more comprehensible and comparable.