Incidence refers to the occurrence of new cases of a particular condition or event within a specified time period. It is often used in epidemiology to measure how frequently diseases, such as diabetes or cancer, arise in a population. This helps researchers understand the spread and risk factors associated with these conditions. The incidence rate is typically expressed as the number of new cases per a defined population size, often per 1,000 or 100,000 individuals. This metric is crucial for public health planning and resource allocation, as it provides insights into the health status of a community and the effectiveness of prevention strategies.