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Overview of clinical research design
Daniel M Hartung1, Daniel Touchette
1College of Pharmacy, Oregon State University, Portland, OR 97239, USA. hartungd@ohsu.edu
Summary
This guide explains clinical research designs for new investigators. Understanding observational and experimental studies, including cohort, case-control, and randomized controlled trials, is crucial for valid findings.
Area of Science:
- Clinical Research Methodology
- Epidemiological Study Design
Background:
- Clinical research involves human subjects and requires careful design to ensure valid findings.
- Potential threats to research integrity include bias and confounding, which can lead to inaccurate conclusions.
Purpose of the Study:
- To present fundamental concepts and terminology of clinical research design.
- To provide guidance for new clinical investigators on selecting appropriate study designs.
Main Methods:
- Discussion of observational study designs: cohort, case-control, and cross-sectional studies.
- Explanation of experimental study designs, focusing on the randomized controlled trial (RCT).
- Comparison of strengths and weaknesses of different research methodologies in addressing research questions.
Main Results:
- Observational research, including cohort, case-control, and cross-sectional studies, offers various approaches to clinical investigation.
- Experimental research, particularly RCTs, is robust for establishing causality but can be challenging to implement.
- Bias and confounding are critical issues affecting all clinical research, with uncontrolled observational studies being more susceptible.
Conclusions:
- Experimental research provides the strongest evidence for causality.
- Carefully planned and executed observational research designs offer valuable alternatives when experimental studies are not feasible.
- Understanding the nuances of each design is essential for conducting rigorous clinical research.
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