Update 2, 6.6.14: Due to the criticism of this study on the web, I have reanalyzed a part of this study. See my comments here. We should by now know that that which we call a rose; by any other name would smell as sweet; but it seems we still haven’t quite internalized the message.…
Approximate Bayesian Computation (ABC) is an umbrella term for a class of algorithms and ideas that allow performing an approximate estimation of the likelihood / posterior for stochastic simulation models when the likelihood cannot be explicitly calculated (intractable likelihood). To give you the idea in a nutshell: to approximate the likelihood, consider that for a…
Since a few years, various subsamples of Jörn Pagel, Joseph Chipperfield, Björn Reineking and I have been teaching an introductory summer school in Bayesian statistics. In previous years, we were in Bayreuth 2011 Bayreuth 2012, Göttingen 2013 and Freiburg 2013. This year, we will be in a beautiful field station close to Bergen, Norway. The…
Yesterday, I gave my first webinar, or online lecture if you want. The occasion was that a few people from another university asked me if I could give an introductory lecture about Bayesian statistics, and because traveling would have cost me a full day, I suggested doing a “virtual visit” instead. It’s a funny coincidence…
I just arXived the final version of our technical note “Approximate Bayesian parameterization of a process-based tropical forest model” (coauthored with Claudia Dislich, Thorsten Wiegand and Andreas Huth) that is now accepted and will appear in Biogeosciences soon. There have been a few minor changes in response to reviewer comments on a discussion version of…
Confirmation bias refers to the well-known phenomenon that we tend to favor information that confirms our beliefs. A while ago, I blogged about potential confirmation bias in statistical analysis, and steps that are taken by large projects such as the LHC to avoid this. Another place where confirmation bias can become relevant for scientific studies…
There’s been too many interesting papers in the last weeks for a lone blogger to cover, so I’m glad that other interesting stuff has been discussed elsewhere, e.g. by EEB & flow on the controversy around “Novel Ecosystems”, NIBMS explaining us why there may be no species below 1 mm, and Nature reporting on the…
I recently posted about a reply to a PNAS paper in which we show that, contrary to the claim in the original publication, the “true” model does by no means delivers worse predictions for chaotic population dynamics than time-series methods without any specific mechanism underlying, provided appropriate statistical estimation methods are used. To be clear,…
Biogeosciences just published a discussion paper on a project I have been working on for quite a while now, namely on likelihood approximations for stochastic forest models (see also our review on the topic of simulation-based inference in general). From the technical side, it may be interesting that we don’t use Approximate Bayesian Computation (ABC),…
I just returned from our Summer School on Bayesian Statistics that we held in the mountains around Freiburg. Thanks to all the participants as well as my fellow lecturers Jörn Pagel and Joe Chipperfield for the really amazing time up there in the hut, hope to see you all soon!
… but does “model-free” forecasting really outperform the “true” model? I’ve been busy in the last while, which is both the reason why it has been quiet on this blog and why I didn’t manage to write earlier about a note that we submitted three weeks ago to the arXiv. The note responds to a…
As in the last years, we organize a course in Bayesian statistics this summer. See invitation below, feel free to distribute widely. 3rd International Summer School An Introduction to Bayesian Modeling for Ecologists in Freiburg (Germany) 28th July to 2nd August 2013 Motivation Bayesian inference is an increasingly used statistical framework in ecology, but…
A comment by Deborah Mayo on a recent post by Andre Gelman started a heated and surprisingly subtle discussion on the correct (frequentist) definition of the p-value that currently continues on Larry Wasserman blog. Read for yourself – I for myself am still happy to write p(D>d|H0) ;).
A comment on a recent post gave me the motivation to try out the new EasyABC package for R, developed by Franck Jabot, Thierry Faure, Nicolas Dumoulin and maintained by Nicolas Dumoulin. Approximate Bayesian Computation (ABC) is a relatively new method that allows treating any stochastic model (IBM, stochastic population model, …) in a statistical…
It seems that the final publication of our special issue on species distribution models and the niche is drawing nearer, and to bridge the time for the (admittedly, probably sizable) group of those are checking their RSS feeds daily in expectation of this event, I would like to highlight three other papers of this special…
I said this before: it’s fascinating to see phylogenetic and phylogeographic methods being applied to linguistic and anthropological studies. A new example of that is a paper in Science, “Mapping the Origins and Expansion of the Indo-European Language Family” led by Remco Bouckaert that came out today. They use BEAST with basic vocabulary data from…
Our new perspective paper on “Connecting dynamic vegetation models to data – an inverse perspective” is now available online at the Journal of Biogeography (see also this post by my coauthor James Dyke). The paper is a part of a special issue on distribution models “The ecological niche as a window to biodiversity” that will…
As last year, we’ll do a summer school on Bayesian modeling in Bayreuth. See the invitation below, and feel free to circulate widely!!! Motivation Statistical modeling with Bayesian methods has become increasingly popular in ecology, but the techniques required for doing so are not part of the standard curriculum in most Universities. Our aim for…
Approximate Bayesian Computing and similar techniques, which are based on calculating approximate likelihood values based on samples from a stochastic simulation model, have attracted a lot of attention in the last years, owing to their promise to provide a general statistical technique for stochastic processes of any complexity, without the limitations that apply to “traditional”…
Tomorrows issue of Nature has an interesting interview with Uri Simonsohn, a researcher that has been investigating several cases of data fabrication in psychology by requesting the raw data and looking for statistical anomalies. In the interview, he explains that The basic idea is to see if the data are too close to the theoretical…
theoretical ecology 