volume 10, Article number: 3870 (2019)
Integrated climate-economy models pretend to show the fate of the planet and its economy several decades ahead, while uncertainty is so wide as to render any expectations for the future meaningless. In economics, models universally known to be wrong continue to play a role in economic policy decisions, while the neologism ‘mathiness’ has been proposed for the use of mathematics in models to veil ideological stances. Disingenuous pricing of opaque financial products is held as partly responsible for the onset of the last recession: modellers chose to calibrate the pricing of bundles of mortgages based on data for the real estate market in an up-swing period. Needless to say, these calibrations conveniently ignored what would happen when the market took a turn for the worse.
Transport policy offer a curious example where a model requires as an input how many people will be sitting in a car on average decades from now. See ref. 1 for the references to the cases just described. More examples are described in ref. 6, portraying flawed models used to justify unwise policies in evaluation of fisheries’ stock, AIDS epidemics, mill tailing, coastal erosion, and so on. Among those, studies for the safety of an underground disposal of radioactive waste stand out for providing what the authors in6 call “A million years of certainty”, achieved thanks to a huge mathematical model including 286 sub-models.
- Memento Fig. 1.
- Mathematical modelling could benefit from structure and standards based on statistical principles including a systemic appraisal of model uncertainties and parametric sensitivities.
- Statistics could help by internalising these into its own syllabi and practices.
- Models–including algorithms, should be made inherently interpretable.
- For key models used in policy, peer review should be extended to include auditing by an extended community involving a plurality of disciplines and interested actors, leading to model pedigrees, as discussed on this journal3 and more diffusely in ref. 1.
- Audits could be used to uncover a model’s underlying, unspoken, metaphors1.
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Competing interestsThe author declares no competing interests.
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