Master Study Validity: Bias, Confounding & DAGs Visual Guide

Stop letting systematic errors ruin your research!

Whether you're a medical student, MPH candidate, or researcher, understanding the nuances of bias and confounding is critical for acing exams and publishing high-quality work.

This EpiVisuals Pack 3 by Dr. Oussama Wail Bouhentala MD provides a comprehensive, visual roadmap to navigating the most complex challenges in epidemiological study design.

What’s inside this 8-card visual pack:

• The Bias Taxonomy: A master classification tree of selection bias, information bias, and confounding.

• Selection & Information Bias: Deep dives into Berkson’s bias, the Healthy Worker effect, recall bias, and the Hawthorne effect.

• Confounding & DAGs: Master the three criteria for a confounder and learn to draw Directed Acyclic Graphs (DAGs) to identify backdoor paths and colliders.

• Effect Modification: Learn why interaction is a finding to report, not a bias to remove.

• Internal vs. External Validity: Understand the trade-offs between trial control and real-world generalisability.

• Control Strategies: A master reference for managing error at the design, analysis, and reporting stages.

This printable PDF download features 8 high-resolution, A4 print-ready study cards.

Perfect for USMLE prep, MPH coursework, or as a desk reference for public health professionals. Download your pack and ensure your research is built on a solid foundation!