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 Conférence L Thaler : Rosemary Grant & Peter Grant Bahn

Le vendredi 13 mai 2016 - Amphithéatre de la Délégation CNRS - 11h30

Ecological research often produces messy data that necessitates flexible and complex models. However, complex models can overfit data, leading to a decoupling between goodness-of-fit and predictive power of the model, making goodness-of-fit an unsuitable evaluation measure. The alternative is to hold out test data for evaluation. However, when autocorrelation is present in model residuals, training and test can lack independence and model evaluation will be overly optimistic. I discuss strategies for decoupling training and test data in the context of species distribution models. While these strategies can reduce the underestimation of model error, they can introduce over-estimation of error by introducing extrapolation in variable space. This problem can be addressed by explicitly testing for analog conditions between training and test data, leading to realistic error estimates.

La conférence Louis Thaler est organisée dans le cadre des Séminaires d’Ecologie et d’Evolution de Montpellier, avec le soutien du LabEx CeMEB.

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