Overadjustment – an important bias hiding in plain sight

Anita van Zwieten, Fiona M Blyth, Germaine Wong and Saman Khalatbari-Soltani

Epidemiologists are generally well equipped to design and conduct studies that minimise various types of bias, so as to obtain the most accurate estimates possible and therefore high-quality evidence. In observational studies, some types of bias, like confounding, have received a lot of attention, while others have been overlooked. One that has been neglected is overadjustment bias, which occurs when researchers adjust for an explanatory variable on the causal pathway from exposure to outcome when seeking to estimate the total effect.

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Proposing a new indicator to assess health disparities: measuring inequalities in causes of death

Iñaki Permanyer and Júlia Almeida Calazans

Policymakers and scholars are increasingly interested in monitoring and curbing health inequalities. Much is known about the main causes of death and how mortality has been shifting from most deaths around the world being caused by communicable diseases towards most being due to non-communicable causes.

However, less is known about the heterogeneity in these causes of death. Are people in some countries dying from an increasingly varied set of causes? Measuring how ‘similar’ or ‘dissimilar’ the different causes of death are can help us understand global health inequalities and patterns of mortality.

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