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Concurrent Evidence

Issue #72

Data, Numbers

On 7 March, Tsuyoshi Hondou and Ismael Rafols posted a blog entry on Leidenmadtrics called “Concurrent Evidence: A Framework for Using Evidence from Multiple Disciplines”. The issue is one about the right interpretation for the right data. The authors explain: “In this blog post, we present two prominent examples of how the use of narrow disciplinary advice led to questionable policy choices.”¹ Both cases come from the natural sciences, and serve to illustrate the risk of looking too narrowly at one firm of evidence in complex situations.


The first case involved the likelihood of a tsunami near Fukushima: “Using as evidence about 100 years of seismograph measurements (i.e. ground movements), geophysicists showed that there was no evidence that a tsunami could hit the locations proposed for the nuclear plants.”¹ Geologists, looking at historical data thousands of years old made a different assessment, which they reported to the government, but “... the Japanese government listened to the advice given by seismology (physics) rather than by geology, despite a longer observation record from the latter – with the well-known disastrous consequences.”¹ 


The second case involved the transmission of COVID-19 infections: “It was initially thought that COVID-19 infection was due to physical contact and droplets, and therefore appropriate prevention measures were thought to be disinfection and shielding. This advice was based on the common perception of medical doctors, who extrapolated from the dogma that airborne infection is restricted to tuberculosis, measles, and chickenpox. However, it was later shown by researchers with expertise in physics that masks and ventilation - the key to prevention against airborne infection - are much more effective than conventional prevention measures against infections.”¹  


While the cases both involve government mistakes, the second case in particular applies broadly to all countries suffering from the pandemic. The common thread is that decision-makers looked too narrowly by making decisions based on established assumptions without looking more broadly at evidence from sources that did not fit their preconceptions. It is hard for decision-makers to look at broader evidence that takes unfamiliar contextual information into account, which may include evidence that the policy makers do not understand. This is why the authors recommend involving a wide variety of experts in a common discussion about complex issues where a single source may not suffice.


1: Hondou, Tsuyoshi, and Ismael Rafols. ‘Concurrent Evidence: A Framework for Using Evidence from Multiple Disciplines’, 7 March 2024.


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