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we have never been unable to develop a reliable predictive model

November 10, 2019

An alarming entry in The Guardian about the huge proportion of councils in the UK using machine-learning software to allocate benefits, detect child abuse or claim fraud. And relying blindly on the outcome of such software, despite their well-documented lack of reliability, uncertainty assessments, and warnings. Blindly in the sense that the impact of their […]

projection predictive input variable selection

November 2, 2015

Juho Piironen and Aki Vehtari just arXived a paper on variable selection that relates to two projection papers we wrote in the 1990’s with Costas Goutis (who died near Seattle in a diving accident on July 1996) and Jérôme Dupuis… Except that they move to the functional space of Gaussian processes. The covariance function in […]

a unified treatment of predictive model comparison

June 16, 2015

“Applying various approximation strategies to the relative predictive performance derived from predictive distributions in frequentist and Bayesian inference yields many of the model comparison techniques ubiquitous in practice, from predictive log loss cross validation to the Bayesian evidence and Bayesian information criteria.” Michael Betancourt (Warwick) just arXived a paper formalising predictive model comparison in an […]

comparison of Bayesian predictive methods for model selection

April 9, 2015

“Dupuis and Robert (2003) proposed choosing the simplest model with enough explanatory power, for example 90%, but did not discuss the effect of this threshold for the predictive performance of the selected models. We note that, in general, the relative explanatory power is an unreliable indicator of the predictive performance of the submodel,” Juho Piironen […]

Posterior predictive p-values and the convex order

December 22, 2014

Patrick Rubin-Delanchy and Daniel Lawson [of Warhammer fame!] recently arXived a paper we had discussed with Patrick when he visited Andrew and I last summer in Paris. The topic is the evaluation of the posterior predictive probability of a larger discrepancy between data and model which acts like a Bayesian p-value of sorts. I discussed […]