Population attributable fraction in textbooks: Time to revise

Area of Science:

• Epidemiology
• Biostatistics
• Public Health

Background:

• Population attributable fraction (PAF) is a key metric for evaluating public health interventions and disease risk.
• Misuse of PAF in research literature necessitates a review of its fundamental concepts and applications.
• Current educational materials may not adequately prepare researchers for accurate PAF utilization.

Purpose of the Study:

• To critically review the definition, calculation, interpretation, and assumptions of PAF as presented in academic textbooks.
• To identify and highlight significant shortcomings in the existing pedagogical approaches to PAF.
• To propose a framework for improving the teaching of PAF in scientific literature.

Main Methods:

• A systematic review of 43 relevant textbooks was conducted.
• The content analysis focused on how PAF, its calculation methods, and related concepts were presented.
• Shortcomings and areas for improvement in textbook explanations were identified.

Main Results:

• The Levin formula for PAF calculation was found in 67% of textbooks, but often without adjustment for confounding.
• Only 9% of textbooks recommended the Miettinen formula or its generalization for confounding-adjusted PAF.
• Advanced concepts like generalized impact fraction were rarely discussed.

Conclusions:

• Existing textbooks often present an incomplete or potentially misleading approach to calculating PAF.
• There is a critical need to revise textbook content to include more robust methods for PAF calculation, particularly those addressing confounding.
• Implementing a standardized framework for teaching PAF is recommended to improve its accurate application in research.