The incidence rate is a measure used in epidemiology to determine how often new cases of a disease occur in a specific population over a defined period. It is typically expressed as the number of new cases per 1,000 or 100,000 individuals at risk. This rate helps public health officials understand the spread of diseases like COVID-19 or influenza. Calculating the incidence rate involves dividing the number of new cases by the total population at risk during a certain time frame, then multiplying by a constant to standardize the figure. This metric is crucial for identifying trends and guiding interventions in public health.