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. 2025 Apr 22;15(1):13879.
doi: 10.1038/s41598-025-92403-z.

Explaining international differences in excess mortality due to Covid-19

Donya Brown  1 , Martina Dattilo  2 , James Rockey  3
Affiliations

Explaining international differences in excess mortality due to Covid-19

Donya Brown et al. Sci Rep. .

Abstract

Many explanations have been advanced for why the frequency of deaths associated with Covid-19 varied so much across countries. Previous work has provided evidence that numerous social, economic, and environmental factors correlate with Covid-19 outcomes. One problem researchers face in identifying which of these explanations are best able to explain cross-country variation is that the number of these explanations is too large to be usefully included in a single regression model. This paper uses Bayesian Model Averaging (BMA) to address this problem, focusing on excess mortality to ensure meaningful comparisons across countries. The results suggest that a key determinant of countries' success in containing Covid-19 has been the strength of the Rule of Law. We also find evidence that rainfall and seaborders are key potential explanations for differences in excess mortality.

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Conflict of interest statement

Declarations. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Excess Mortality (year 2020). Source: Created by the authors using RStudio (Version 1.1.456).
Fig. 2
Fig. 2
Comparison of the Economist and Wang et al. Datasets versus the WHO Data (year 2020).
Fig. 3
Fig. 3
Determinants of cross-country differences in excess mortality: excluding policy.
Fig. 4
Fig. 4
Determinants of cross-country differences in excess mortality: pre-determined covariates.
Fig. 5
Fig. 5
Determinants of cross-country differences in excess mortality: all covariates.
See this image and copyright information in PMC

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