What is the impact of reducing air pollution on mortality? And how does this compare to reducing smoking? Or the impact of salt reduction for preventing cardiovascular deaths? The answer depends on the perspective: effects may not be relevant from the individual perspective, but could be relevant from the population perspective when there is an important number of preventable deaths.

These videos, originally part of the Cochrane Learning Live webinar series, explain how presentation of effect sizes from the individual or population perspective can influence judgments about the importance of these effects and prevention strategies. Dr Jos Verbeek provides guidance for systematic review authors on how to consider the individual and the population perspective.

This webinar was part of a collaborative Public Health Network project aimed at all people interested in systematic review methodology in the field of public and occupational health. The videos are of particular interest to Cochrane Systematic Review authors and staff. The presentation is based on the article published in American Journal of Publich Health (Verbeek et al, 2021).

The webinar was delivered in September 2021 and below you will find the videos from the webinar, together with accompanying slides to download [PDF].

Part 1: Presentation
Part 2: Questions and answers

Presenter Bio

Dr Jos Verbeek is an occupational health physician and epidemiologist by training. He has been involved in Cochrane from 2004. He is also a methodologist on several WHO environmental health guidelines.

Part 1: Presentation

Part 2: Questions and answers

Additional materials

Download the slides from the webinar [PDF]