Epidemiology is concerned with groups of subjects belonging to populations, not with each individual subject, and takes into account both the subjects who contract a disease and those who do not. Comparison, thus, is a basic element of this discipline. Measures of frequency, association and impact are the main statistical resources employed in epidemiology to describe the distribution of healthcare problems, establishing a causal relationship between exposure and disease, enabling users to evaluate the impact of preventive measures in the field of public health.
2010 SEICAP. Published by Elsevier Espana. All rights reserved.