General Characteristics and Classification of Study Designs Used in Clinical Anesthesia Research. Part 1

Abstract

This article aims to describe the general characteristics and classification of the most relevant quantitative research designs in anesthesiology.
Scientific research is based on the scientific method, which seeks truth and aims to minimize bias.

A study design refers to the set of procedures and techniques used for data collection and analysis, and its selection depends on multiple factors.
Research designs are classified as Observational Studies (OS) and Experimental Studies (ES)—a distinction that is crucial because it determines the level of evidence they provide.

Observational studies may be descriptive or analytical.
Among the descriptive designs most relevant to anesthesiology are case reports, case series, and cross-sectional studies, while the analytical designs include case-control studies and cohort studies.

Experimental studies encompass randomized clinical trials (RCTs) and quasi-experimental studies.
Controlled RCTs are powerful designs for assessing the effectiveness of an intervention and are often the most appropriate choice for that purpose.

Systematic reviews (SRs) and meta-analyses (MAs) synthesize findings from primary research and, when conducted rigorously, can provide the highest level of evidence.

Understanding the characteristics, strengths, and limitations of each design is essential for conducting rigorous studies, interpreting results critically, and improving evidence-based clinical practice.
The choice of design directly impacts the level of evidence applicable to different clinical scenarios in our specialty.