Types of Descriptive Epidemiological Studies

Epidemiology is a branch of medical science that studies the distribution and determinants of health-related states or events, such as disease, and the factors that determine the presence or absence of such disorders and maladies. Epidemiology is used to help control diseases and other health problems around the world as well as understanding how such disorders can affect society. Descriptive epidemiological studies examine morbidity and mortality in the examined populations. These studies tend to focus on its occurrence and distribution relating to person, place and time.

Case Series

• Case series are reports on a group of patients with a series of cases of specific conditions in which there is no specific control group involved. This study design is often used to identify the beginning or presence of an epidemic. Advantages of case series are that they can help formulate about the malady that is occurring, which can lead to a more descriptive study. Unfortunately, case series cannot be used to test for the presence of valid statistical association.

Cross-sectional Study

• A cross-sectional study, or prevalence study, observes a certain population at a single point in time or during a specific time interval. These studies can survey or assess the health status of a population and information can be obtained from individuals such as history, habits, knowledge and behaviors. Advantages include that exposure and disease status can be simultaneously assessed in a population, provides information about the disease's characteristics and frequency and costs for doing this study are small. Limitations of this study are that you cannot determine if the disease exposure preceded the disease or occurred due to the disease.

Correlational Studies

• Correlational studies, or ecological studies, examine populations rather than individuals. These descriptive studies focus on the associations between exposures and outcomes in the selected populations. These studies focus on data collected in the past. Advantages of such studies are that they are fast and quick to perform, it can generate new hypothesis and new risk factors can be identified. Disadvantages are that this study cannot link exposure with disease in individuals since those with the disease may not have been exposed, confounding factors cannot be controlled and disease rates are observed at a group level and do not reflect association at the individual echelon.