Critical engagement on the selection and reporting of biometeorological indices.

Over the past four decades, a plethora of biometeorological indices has emerged. These are enabling the quantification and spatiotemporal comparison of climatic suitabilities and risks for a wide range of activities across indoor and outdoor settings. The relative mathematical simplicity of many of these indices, and the increasing availability of high-quality gridded data, mean that human biometeorological conditions can be computed rapidly and at scale. This is reflected in the literature, with considerable increases in quantitative biometeorological studies over the same period. However, with this computational ease comes a risk of the inadvertent output of spurious results; if the indices have not been carefully selected for their appropriate use for a given location, set of activities, and inherent assumptions. Where these biometeorological index outputs are used in informing policy, which ideally they should be, this risk of misinformation feeding maladaptation needs to be carefully mitigated through a thorough assessment of index applicability, suitability and validity. This paper sets out a conceptual selection framework that is guided by these three variables, following application of this approach in a range of settings, advocating for careful pre-assessment evaluation of indices in their selection. CLINICAL TRIAL REGISTRATION: Not applicable.