Frequency Measures of Epidemiological Studies

Abstract

This article explained the measures of frequency and association that are used in observational epidemiological data analysis. The observational studies include cohort, case-control and cross-sectional. In epidemiology, most of the variables are nominal with only two categories like exposed or unexposed, male or female, case or control, so ratios, rates, and proportions are used in the analysis of these types of dichotomous variables. Different fictional data from different studies were used to calculate the incidence rate, relative risk, mortality rate, odds ratio and prevalence of diseases. The odds ratio and relative risk are called measures of association simply because they quantify the relationship between exposure and outcome. Incidence rate, relative risk, and mortality rate were calculated in cohort studies; the odds ratio was determined in a case-control study while prevalence was calculated in a cross-sectional study. The appropriate measure to be used depends on the type of the research.