Related Experiment Video
Updated: Jun 19, 2026

Observational Study Protocol for Repeated Clinical Examination and Critical Care Ultrasonography Within the Simple Intensive Care Studies
Published on: January 16, 2019
Case-control studies--an efficient observational study design
Karlijn J van Stralen1, Friedo W Dekker, Carmine Zoccali
1Department of Medical Informatics J1b, Academic Medical Center, Amsterdam, The Netherlands.
Abstract:
Case-control studies are an efficient research method for investigating risk factors of a disease. The method involves the comparison of the odds of exposure in a patient group with that of the odds of exposure in a control group. As only a minority of the population is included in the study, less time can be devoted to those who remain free of the disease of interest. The design of a case-control study can be complex due to the selection of the appropriate cases and controls. Cases can be identified in a prospective and retrospective manner from various sources. Controls can be obtained via the patient, random digit dialing or in a hospital and all at different points in the time period of the study. All options have their own advantages and disadvantages. Furthermore, different forms of bias, such as recall bias and selection bias, can occur. When appropriately designed, case-control studies can provide the same information as in a cohort study, in a more rapid and efficient manner.
Related Concept Videos
Study Designs in Epidemiology
Observational studies are those where the researcher does not intervene but rather observes natural variations. They include cross-sectional, cohort, and case-control studies.
Observational Studies
There are three types of observational studies – Prospective, retrospective, and cross-sectional.
Prospective Study
Prospective studies, also known as longitudinal or cohort studies, are carried out by collecting future data from groups sharing similar characteristics. One example of...
Types of Biopharmaceutical Studies: Controlled and Non-Controlled Approaches
Non-controlled studies, commonly employed for initial exploration, lack a control group, rendering them susceptible to biases and external influences. In contrast, controlled...
Study Design in Statistics
Does aspirin reduce the risk of heart attacks? Is one brand of fertilizer more effective at growing roses than another? Is fatigue as dangerous to a driver as the influence of alcohol? Questions like these are answered using randomized experiments with proper...
Data Collection by Observations
An astronomer viewing the motion and brightness of stars in the sky and recording the data is an example of observational data collection. A botanist recording...
Introduction to Epidemiology