What does 'incidence' measure in epidemiology?

Incidence in epidemiology specifically measures the number of new cases of a disease that occur in a specified population within a defined period of time. This metric provides important insights into the dynamics of diseases, allowing researchers and public health officials to understand how quickly a disease is spreading and to identify trends over time.

By focusing on new cases, incidence helps to distinguish between the total number of individuals affected by a disease at a certain time (prevalence) and the rate at which new cases are being generated. Understanding incidence is crucial for effective disease control and prevention strategies, as it can inform resource allocation and intervention efforts based on the current outbreak status.

Additionally, incidence can be used to calculate incidence rates, which provide context related to the population at risk, thus allowing for comparisons across different groups and time periods. This is fundamental for health planning and policy decision-making.