## a paradox in decision-theoretic interval estimation (solved)

Posted in pictures, Statistics, Travel, University life with tags , , , , , , , , , , , on October 4, 2012 by xi'an

In 1993, we wrote a paper [with George Casella and Gene/Juinn Hwang] on the paradoxical consequences of using the loss function

$\text{length}(C) - k \mathbb{I}_C(\theta)$

(published in Statistica Sinica, 3, 141-155) since it led to the following property: for the standard normal mean estimation problem, the regular confidence interval is dominated by the modified confidence interval equal to the empty set when is too large… This was first pointed out by Jim Berger and the most natural culprit is the artificial loss function where the first part is unbounded while the second part is bounded by k. Recently, Paul Kabaila—whom I met in both Adelaide, where he quite appropriately commented about the abnormal talk at the conference!,  and Melbourne, where we met with his students after my seminar at the University of Melbourne—published a paper (first on arXiv then in Statistics and Probability Letters) where he demonstrates that the mere modification of the above loss into

$\dfrac{\text{length}(C)}{\sigma} - k \mathbb{I}_C(\theta)$

solves the paradox:! For Jeffreys’ non-informative prior, the Bayes (optimal) estimate is the regular confidence interval. besides doing the trick, this nice resolution explains the earlier paradox as being linked to a lack of invariance in the (earlier) loss function. This is somehow satisfactory since Jeffreys’ prior also is the invariant prior in this case.

## news from Elsevier

Posted in Books, Statistics, University life with tags , on July 4, 2012 by xi'an

Here is an email I got today from Elsevier:

We are pleased to present the latest Impact Factors for Elsevier’s Mathematics and Statistics journals.

 Journal of Multivariate Analysis 0.879

So there are very few journals published by Elsevier in the statistics field, which may explain for the lack of strong support for the boycott launched by Tim Gowers and others. Also, the impact factors are not that great either. Not so suprising for Statistics and Probability Letters, given that they publish a high number of papers of uneven quality, but also gets a minimal 1. So it does not make too much sense for Elsevier to flout such data. (Once again, impact factors should not be used for assessing the quality of a journal and even less of a paper!)

## new Elsevier journal!

Posted in Books, Statistics, University life with tags , , on May 11, 2012 by xi'an

Elsevier is launching a new journal called Spatial Statistics, whose goal is…

“…to be the leading journal in the field of spatial statistics. It publishes articles at the highest scientific level concerning important and timely developments in the theory and applications of spatial and spatio-temporal statistics. It favors manuscripts that present theory generated by new applications, or where new theory is applied to an important spatial problem.”

## About commercial publishers

Posted in Books, R, Statistics, University life with tags , , , , , , , on September 20, 2011 by xi'an

Julien Cornebise has [once again!] pointed out a recent Guardian article. It is about commercial publishers of academic journals, mainly Elsevier, Springer, and Wiley, with a clear stand from its title: “Academic publishers make Murdoch look like a socialist“! The valuable argument therein is that academic publishers make hefty profits (a 40% margin for Elsevier!) without contributing to the central value of the journals, namely the research itself that is mostly funded by public or semi-public bodies. The publishers of course distribute the journals to the subscribers, but the reported profits clearly show that, on average, they spend much less doing so than they charge… Here are some of the institutional rates (can you spot Elsevier journals? journals published by societies? free open access journals?!):

(apart from greed, there is no justification for the top four [Taylor and Francis/Elsevier] journals to ask for such prices! The Journal of Econometrics also charges \$50 per submission! PNAS is another story given the volume of the [non-for-profit] publication: 22750 pages in 2010, meaning it is highly time to move to being fully electronic. The rate for Statistics and Computing is another disappointment, when compared with JCGS. )

The article reports the pressure to publish in such journals (vs. non-commercial journals) because of the tyranny of the impact factors. However, the reputation of those top-tier journals is not due to the action of the publishers, but rather to the excellence of their editorial boards; there is therefore no foreseeable long-term impact in moving from one editor to another for our favourite journals. Moreover, I think that the fact to publish in top journals is more relevant for the authors themselves than for the readers when the results are already circulating through a media like arXiv. Of course, having the papers evaluated by peers in a strict academic mode is of prime importance to distinguish major advances from pseudo-science; however the electronic availability of papers and of discussion forums and blogs implies that suspicious results should anyway be detected by the community. (I am not advocating the end of academic journals, far from it!, but an evolution towards a wider range of evaluations via Internet discussions, as for the DREAM paper recently.) The article also mentions that some funding organisms impose Open Access publishing. However, this is not the ideal solution as long as journals also make a profit on that line, by charging for open access (see, e.g., PNAS or JRSS)! Hence using another chunk of public (research) money towards their profits… My opinion is that everyone should make one’s papers available on-line or better via arXiv. And petition one’s societies for a tighter control of the subscription rates, or even a move to electronic editions when the rates get out of control.

PS-Here is a link to an Australian blog, the Conversation, where some publishers (Wiley and Elsevier) were interviewed on these points. I will not comment, but this interview is quite informative on the defense arguments of the publisher!