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Updated: Oct 28, 2025

A Clinical Trial Assessing the Safety, Efficacy, and Delivery of Olive-Oil-Based Three-Chamber Bags for Parenteral Nutrition
Published on: September 20, 2019
Study Designs in Clinical Research
April E Mendoza1, D Dante Yeh2
1Division of Trauma, Emergency Surgery, and Surgical Critical Care, Department of Surgery, Massachusetts General Hospital, Boston, Massachusetts, USA.
Abstract:
The quality of scientific literature is judged by study design, validity, and applicability to unique patient populations. We searched the available literature to explore the hierarchy of evidence, explain research fundamentals such as sample size calculation, and discuss common study designs employed in surgical research and the interpretation of trial designs. Each unique study design has restraints created by some degree of systematic errors and bias. This article provides definitions for the scientific boundaries of case control, retrospective, before-and-after, prospective observational, randomized controlled designs, and meta-analyses. Critical thinking and appraisal of the literature is a skill that requires lifelong training and practice. Clinical research education and design need to garner more attention in the medical community.
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