Archive for Brexit

no haggis for Burns night!

Posted in Statistics with tags , , , , , , , , , , , , , , , on January 25, 2021 by xi'an

so long, U.K., and thanks for all the fish

Posted in Statistics with tags , , , , , , , , , , on December 31, 2020 by xi'an

understanding elections through statistics [book review]

Posted in Books, Kids, R, Statistics, Travel with tags , , , , , , , , , , , , , , , , , , , , , , , , on October 12, 2020 by xi'an

A book to read most urgently if hoping to take an informed decision by 03 November! Written by a political scientist cum statistician, Ole Forsberg. (If you were thinking of another political scientist cum statistician, he wrote red state blue state a while ago! And is currently forecasting the outcome of the November election for The Economist.)

“I believe [omitting educational level] was the main reason the [Brexit] polls were wrong.”

The first part of the book is about the statistical analysis of opinion polls (assuming their outcome is given, rather than designing them in the first place). And starting with the Scottish independence referendum of 2014. The first chapter covering the cartoon case of simple sampling from a population, with or without replacement, Bayes and non-Bayes. In somewhat too much detail imho given that this is an unrealistic description of poll outcomes. The second chapter expands to stratified sampling (with confusing title [Polling 399] and entry, since it discusses repeated polls that are not processed in said chapter). Mentioning the famous New York Times experiment where five groups of pollsters analysed the same data, making different decisions in adjusting the sample and identifying likely voters, and coming out with a range of five points in the percentage. Starting to get a wee bit more advanced when designing priors for the population proportions. But still studying a weighted average of the voting intentions for each category. Chapter three reaches the challenging task of combining polls, with a 2017 (South) Korea presidential election as an illustration, involving five polls. It includes a solution to handling older polls by proposing a simple linear regression against time. Chapter 4 sums up the challenges of real-life polling by examining the disastrous 2016 Brexit referendum in the UK. Exposing for instance the complicated biases resulting from polling by phone or on-line. The part that weights polling institutes according to quality does not provide any quantitative detail. (And also a weird averaging between the levels of “support for Brexit” and “maybe-support for Brexit”, see Fig. 4.5!) Concluding as quoted above that missing the educational stratification was the cause for missing the shock wave of referendum day is a possible explanation, but the massive difference in turnover between the age groups, itself possibly induced by the reassuring figures of the published polls and predictions, certainly played a role in missing the (terrible) outcome.

“The fabricated results conformed to Benford’s law on first digits, but failed to obey Benford’s law on second digits.” Wikipedia

The second part of this 200 page book is about election analysis, towards testing for fraud. Hence involving the ubiquitous Benford law. Although applied to the leading digit which I do not think should necessarily follow Benford law due to both the varying sizes and the non-uniform political inclinations of the voting districts (of which there are 39 for the 2009 presidential Afghan election illustration, although the book sticks at 34 (p.106)). My impression was that instead lesser digits should be tested. Chapter 4 actually supports the use of the generalised Benford distribution that accounts for differences in turnouts between the electoral districts. But it cannot come up with a real-life election where the B test points out a discrepancy (and hence a potential fraud). Concluding with the author’s doubt [repeated from his PhD thesis] that these Benford tests “are specious at best”, which makes me wonder why spending 20 pages on the topic. The following chapter thus considers other methods, checking for differential [i.e., not-at-random] invalidation by linear and generalised linear regression on the supporting rate in the district. Once again concluding at no evidence of such fraud when analysing the 2010 Côte d’Ivoire elections (that led to civil war). With an extension in Chapter 7 to an account for spatial correlation. The book concludes with an analysis of the Sri Lankan presidential elections between 1994 and 2019, with conclusions of significant differential invalidation in almost every election (even those not including Tamil provinces from the North).

R code is provided and discussed within the text. Some simple mathematical derivations are found, albeit with a huge dose of warnings (“math-heavy”, “harsh beauty”) and excuses (“feel free to skim”, “the math is entirely optional”). Often, one wonders at the relevance of said derivations for the intended audience and the overall purpose of the book. Nonetheless, it provides an interesting entry on (relatively simple) models applied to election data and could certainly be used as an original textbook on modelling aggregated count data, in particular as it should spark the interest of (some) students.

[Disclaimer about potential self-plagiarism: this post or an edited version will eventually appear in my Books Review section in CHANCE.]

a journal of the plague year [deconfited reviews]

Posted in Books, Kids, pictures, Running, Wines with tags , , , , , , , , , , , , , , , , , , , , , , , , on July 4, 2020 by xi'an

Found a copy of Humans by Donald Westlake on the book sharing shelves at Dauphine. And read it within a few hours, as it is very light reading but quite funny nonetheless. If hardly ranking as a mystery novel. Or crime novel, unless the crime is Gaiacide and the criminal God. Reminded me of the equally light Bobby Dollar series by Tad Williams. As the main character is an angel, falling for humans as he tries to steer them towards the Armageddon. The setting is the early 1990s, with the main scares being atomic disaster (Chernobyl) and the AIDS pandemic. Plus the rise of environmental worries and of Chinese autocracy. I put it back on the shelves on my next visit to Dauphine, hopefully for someone else to enjoy!

Baked radish stems with basil for making pesto, with a bit more bitterness than usual. Cooked plenty of fennel since this is fennel season. Continued making my weekly rhubarb preserve. Keeping the garden active, now watching squash vines invading new territory, hopefully with an eatable reward in the Fall. Tomatoes are growing incredibly fast as well..! Saw another fox in the Parc before official opening times, quite close if speeding away from me and barely avoiding bumping in a pair of greyhounds which fortunately sounded completely unconcerned.

Watched Children of Men after an exhausting week online for a grant panel. While a parabola for the coming collapse of civilisation under political, biological and environmental apocalypses [is there any meaning to use apocalyse in the plural tense!?] and a premonitory tale on Brexit and the buttressing of Britain [or Trump and his Big Wall mania] induced by anti-immigrant rethorics, the film is over the top in terms of plot and action, with symbolism taking over realism, even on the slightest degree, every shot being filled with references to religions and arts (like the Pink Floyd flying pig), to previous environmental disasters (with long shots of burning cows reminiscent of the mad cow crisis) and geo-political upheavals (including a Hamas type protest in the refugee camp, with a short appearance of a jeep with a French flag more reminiscent of the liberation of Paris in August 1944). Characters are charicaturesque, with a very Manichean division between very few good ones and mostly bad ones. The most ridiculous part of the scenario may well be the battle scene in the refugee camp [tanks versus pistols!]… Once again stunned by all the awards and praise piled upon that film.

Read two more volumes of the Witcher [bought during BayesComp for my son!]. One being Sword of Destiny and a series of short stories, like the first volume. The second Blood of Elves and the beginning of the novels. The first season on TV borrows mostly from the first two collections of short stories. Which are somewhat better than the novel, as the latter is very slow paced and overly sentimental. Not terrible, mind.

Completed with uttermost reluctance the Horde du Contrevent [translating as the windwalkers] by Alain Damasio (no English translation available, but an Italian version, l’Orda del Vento,  is). Book that I again picked for figuring in Le Monde 100 bes&tc list! And felt like constantly fronting a strong, icy wind when going through the pages of that unusual book. The style is unpleasant and rather pretentious, with numerous puns in French.. The story is one of a (religious? mystical?) group walking against the wind(s) for decades to reach the source of these winds and to find the last types of wind no one has ever met. Their dreary pilgrimage is described by the 23 membres of the group, called the Horde, with a heavy-handed typographical symbol at the start of each paragraph identifying who’s speaking (and a convenient page marker with all these symbols). A bit heavy handed as a polyphonic novel (appropriately composed in a Corsican retreat!) and even more in the crypt-Nietschean philosophy it carries… The background universe there is somehow eco-steam-punk, with the wind producing most of the energy. The most exciting part involves rather realistic ice climbing. However, I clearly stand in the small minority of those less than impressed by the book as it is highly popular among French readers, one of the highest printings in the Folio collection, with side products a BD (above) and a movie (in the making?). (And enough votes from fans to almost reach the 10 most favourite novels in Le Monde list. )

punch [him] back, Britain!

Posted in Statistics with tags , , , , , , , on December 12, 2019 by xi'an