Epidemiological measures: application and interpretation in real-life scenarios according to epidemiological study designs

Frequency, association and impact measures are key concepts in clinical epidemiology; however, it has been found that a considerable proportion of health students and professionals have no knowledge of how to use or interpret them when reading a scientific paper or conducting research. This article aims to explain the main epidemiological measures, how they are used, derived and interpreted. They are approached from the perspective of each of the most frequently used types of primary quantitative research studies (randomized clinical trials, cohort studies, case-control estudies and cross-sectional studies) in order to provide the reader with the context in which they are used. Moreover, the process for calculating and interpreting each result in a real setting is explained using clinical examples for a better understanding of these concepts and in order to prevent their use from becoming just a mechanical or repetitive exercise.