Absolute risk represents the probability of an event occurring in a population over a specific period. It is determined by dividing the number of individuals experiencing the event by the total number of individuals in the population at risk. For instance, if 100 individuals out of a group of 1000 develop a certain disease within five years, the absolute risk of developing that disease over that period is 10%. This value offers a direct measure of the likelihood of an event in a defined group.
This measure is critical for understanding the real-world impact of various exposures and interventions. Unlike relative risk, which can exaggerate the perceived effect by comparing risk in exposed versus unexposed groups, it provides a baseline for decision-making in public health and clinical practice. Understanding the historical context of risk assessment highlights the evolution from relying solely on relative measures to incorporating absolute figures for a more nuanced and practical evaluation of health risks and benefits.