Archive for CHANCE

Seminal ideas and controversies in Statistics [book review]

Posted in Books, Mountains, pictures, Statistics, Travel, University life with tags , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , on May 24, 2025 by xi'an

CRC Press sent CHANCE this book for review. Since the topic was of clear interest to me, with an author who significantly contributed to the field—my only recollection meeting Roderick Little was during the Australian Statistical Conference in Adelaïde, in 2012, at the start of my Oz 2012 Tour!—, I took the opportunity of the nearest weekend to browse through Seminal ideas and controversies in Statistics. I like very much the idea of selecting a dozen key papers in the history of Statistics and of discussing why. In fact, this reminded me of my classics seminar, which lasted the few years I was 100% in charge of the Master program in Dauphine (and which I hope I could restart!). Checking the list of the papers I then suggested my students, I see some overlap with 9 papers out of the 15 groups. (I also remember Steve Fienberg making suggestions for that list, while he was spending a sabbatical in Paris at CREST.) Given that community of focus and purpose, and contrary to my wont, I have really very little of substance to criticize or wish about the book. The less when reading the following

“On a personal note, I met Yates [author of a 1984 paper on tests for 2×2 contingency tables discussing the relevance of conditioning on one or both margins], a charming man, when I was a young graduate student who knew next to nothing about statistics; we discussed the joys of traversing the Cuillin Ridge in Skye.”

since completing that ridge remains high in my mountain-climbing bucket-list! (Possibly next year, since we are running an ICMS workshop on the Island.)

The first paper in the series is more than a foundational paper since (The) Fisher’s 1922 paper is about creating (almost) ex nihilo the field of (modern) mathematical statistics. I don’t know if there is any equivalence in other scientific disciplines of such an impact (and of such a man)… Roderick Little manages to convincingly engage with Fisher’s dismissive views on (not yet called) Bayesian analysis, although, to the latter’s defence, the formalisation of Bayesian inference at that time had not yet emerged. The second chapter is discussing Yates’ 1984 paper on tests for 2×2 contingency tables that he wrote 50 years after writing the original one in the first volume of JRSS. Roderick Little adds a detailed Bayesian analysis with the three standard reference priors, Jeffreys’ version proving quite close to Fisher’s exact test (conditional on both margins). The third chapter is aiming at the generic challenge of hypothesis testing, from the well-known opposition between Fisher and Neyman (both on the cover), to questioning the sanity of hard-set thresholds (with a mention of our American Statistician call to abandon (shi)p!). The later (thus) refers to the recent literature on the replicability crisis and the now famous ASA statement on p-values by Ron Wasserstein and Nicole Lazar, analysed in the chapter. But I would have like to read another full section on alternatives to hypothesis testing. While now a niche interest (imho), Fisher’s attempt at creating a posterior distribution without a prior, aka fiducial inference, is discussed in Chapter 4 with the Behrens-Fisher problem as the illustrating example. The chapter feels rather anticlimactic, with the comparison relying on the (Malay) Ghosh and Kim (2001) simulation results.

Birnbaum’s (1962) likelihood principle is the topic of Chapter 5 (and I cannot remember any of my students choosing this paper over the years, although there was at least one). Roderick Little recalls some sentences from the JASA discussion as an appetiser, a reminder of the time when these discussions could turn in scathing attacks. The chapter contains excerpts from Berger and Wolpert (1988)—which they were writing while I was spending a year at Purdue and which I have always recommended to my PhD students, albeit not for the classic seminar. It then moves to the controversies that surround this principle since its inception, in particular those accumulated by Deborah Mayo (also on the cover) as reported on the ‘Og. In the recent years, I have become less excited about the LP, in part due to the imprecision in its statement, which opens the door to conflicting interpretations. And in part due to the scarcity of models with non-trivial sufficient statistics. (I am also wondering if the sufficiency issue we highlighted in our ABC model choice criticism does relate to the mixture example at the end of the chapter.)

The next chapter is one all for compromise, through the calibrated Bayes perspective that credible statements should be close to confidence statements in the long run. Which I remember him presenting at ASC 2012. The concept is found in the very 1984 paper by Don Rubin (also on the cover) that contains the concept behind Approximate Bayesian Computation (ABC). And the chapter proceeds by listing strengths and weaknesses of frequentist and Bayesian perspectives, towards a fusion of both., e.g. though posterior predictive checks.

While the choice of a (general public) paper from Scientific American may sound surprising in Chapter 7, with Efron’s (on the cover) and Morris’ 1977 Stein’s paradox, I cannot but applaud, the more because this was the first paper I read when starting my PhD on the James-Stein estimators. Although this may sound like happening eons ago, the James and Stein (1961) paper—which is my age!—”created a considerable backlash” by toppling unbiasedness from its pedestal and exhibiting a paradox that 1+1+1≠3… Which Little reinterprets via a random effect (or Bayesian hierarchical) model. (And a chapter where I learned that Little’s father was a journalist, a characteristic he shared with Bruce Lindsay, as I found at Blonde, Glasgow, during an ICMS workshop). Relatedly, the next chapter is about the “57 varieties [of regression] paper” by Demptster, Schatzoff and Wermuth (1977). Apparently connected with Heinz 57 varieties of pickles. The paper considers Stein and ridge and variable selections versions for variable selection. The chapter also covers (Bayesian) Lasso and BART, as well as a brief all too brief mention of Spike & Slab priors—with my friend Veronika Ročková missing from the authors’ index!—,  but I was expecting from the title other, robust, forms of regression like L¹ regression and econometrics digressions. Chapter 10 can however been seen as a proxy since covering generalized estimating equations from a 1986 Biometrika paper of Liang and Zeger, with no Bayesian aspect (and an expected appearance of Communications in Statistics B).

Chapter 9 covers the almost immediately classic 1995 paper of Benjamini and Hochbeg on multiple regressions (that Series B turned into a discussion paper ten years later!). Although it spends more time on Berry’s (2012) recommendations than on FDR. The computational Chapter 11 brings together Efron’s (1979) bootstrap [with his picture on the cover] and MCMC, represented by the founding paper of Gelfand and Smith (1990, if mistakenly set in 1988 on p140). A bit of a strange mix imho as the former is more inferential than computational. And not giving the EM algorithm that much space. And not questioning MCMC methods as a good proxy to posterior distributions. Tukey’s Future of Data Analysis (as founding exploratory data analysis) and Breiman’s Two cultures (as launching statistical machine learning) meet in Chapter 12. (With a reminder that the latter invokes Occam’s razor—which may not be that appropriate for hugely overparameterised machine learning black boxes—and…the Rashomon principle! Meaning that distinct models may all fit the same data. Let me nitpickingly add the reference to Ryûnosuke Akutagawa as the author of Rashômon and other stories that Kurosawa adapted in his splendid movie). The chapter contains critical remarks from David Cox, Brad Efron, David Bickel, and Andrew Gelman, with a further section on Little’s view on modelling.

The last three chapters are on design and sampling, in connection with Little’s (and Rubin’s) works in the area. With a 1934 paper of Neyman (whose picture on the cover could have been chosen differently, albeit no fault of Neyman [or of Little!] that his toothbrush style of moustache dramatically got out of fashion!). With a return to calibrated Bayes and a reminiscence of Little’s time at the World Fertility Survey but (apparently) no mention of the probabilistic aspects of modern censuses (that saw my friends Steve Fienberg on the one side and Larry Brown and Marty Wells on the other side argue for and against it!), again relating to the reliance on statistical models. Chapter 14 relates randomized clinical trials to causality, which makes a (worthy) appearance there. Roderick Little also makes a clear case there against the retracted study linking vaccines and autism, a call that will unlikely not reach the current Trump administration and its Secretary of Health.

The book concludes with a list of twenty style and grammar suggestions for improved writing.

As should be crystal-clear from the above, I quite enjoyed the book and would definitely use its reading list in a graduate course whenever the opportunity arises. Once again, some choices are more personal to the author than others, and I would have place more emphasis on the fantastic Dawid, Stone and Zidek (1973)—with Jim Zidek also missing from the author index—, but all make sense in a walk through statistical classics. Let me however regret the absence therein of major actors like, e.g., D. Blackwell, C.R. Rao,  or G. Wahba (except in a stylistic example p199), two of whom were awarded the International Prize in Statistics.

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

Data science ethics [book review]

Posted in Books, Statistics, University life with tags , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , on May 5, 2025 by xi'an

Data science ethics (concepts, techniques and cautionary tales), by David Martens, was published in 2022 by Oxford University Press. The book is inspired by the author’s  course on Data Science and ethics he has been teaching at the University of Antwerp. (With a link to his slides.) The 255p book proceeds by decomposing the ethics of data science into its different steps: data gathering (Chap. 2), data preprocessing (Chap. 3), modelling (Chap. 4), evaluation (Chap. 5), and deployment (Chap. 6). Following the `FAT Flow Framework´, where FAT stands for fairness, accountability, and transparency.

Do not expect much maths, stats, or anything quantitative: this book is mostly about concepts, even though some (mostly well-known) illustrations are provided. Chapter 2 includes a description of encryption (with homomorphic encryption treated in Chapter 4). And somewhat improbably quantum computing. Differential privacy gets a few pages with not a single formula (until Chapter 4, again).

Chapter 3 covers k-anonymity, record linkage, reidentification, (through cautionary tales) and discrimination through biases in the (learning) dataset.  Chapter 4 is defining ε differential privacy with the Laplace randomization as a possible implementation and with no critical stance on the limitations of the concept. The computation limitations of homomorphic encryption are more clearly pointed out. Federated learning is only quickly mentioned. The section about measuring fairness and reducing bias implies that some prior knowledge is available about whom is potentially discriminated and which covariates to add to the model. The last section on explicability of predictions is worthwhile in signalling the difficulty with most (black box) AI but the example opposing an SVM model to a logistic model is not tremendously convincing in that neither model is true.

Chapter 5 addresses the crucial challenge of ethical evaluation in a rather verbose and vague manner. For instance, with no instruction on how to resist adversarial attacks. Or criticising p-hacking and multiple testing while missing the elephant in the room (p-values!). Drifting from the topic when discussing the misdeeds of Diederik Stapel. Most of the same goes about Chapter 6 and its take on ethical deployment, when going through examples such as Google’s policies in China. Or general musing on the impact of AI on societal inequalities (with mentions of companies and CEOs who have since then back-pedalled on their ethical engagement). These chapters are lacking in tools and (more) practical recommendations.

One interesting aspect of the book is the attention paid to the EU(ropean) aspect of these concerns, through the GDPR (General DAta Protection Regulations) adopted by the European Parliament in 2016. (There is also a brief mention of China’s regulations, but no details beyond a reference. Maybe the Chinese edition differs.)

the polls weren’t wrong [alt book review]

Posted in Statistics with tags , , , , , , , , , , , , , , , on April 1, 2025 by xi'an

Stories of your life and Others [book review]

Posted in Books, Kids, University life with tags , , , , , , , , , , , , , , , , , , , , , on March 18, 2025 by xi'an

Just finished the book Stories of your life and Others by Ted Chiang, which like the later Exhalation I deeply enjoyed. The book was published in 2001, with some of its stories appearing as early as 1990, hence this book review is of little relevance when many reviews and commentaries have been published, including academic reviews. (No chance for CHANCE, then!)

“Perhaps you have not noticed that the lower classes are reproducing at a rate exceeding that of the nobility and gentry (…) Consequently, our nation would eventually drown in coarse dullards.” (p.186)

While the original cover seems to cater to old-fashion science-fictions books and magazine of the 1950’s, like Amazing Stories, the contents are much more philosophical than science-fiction-al, even when the universe  (or the physical laws that) Chiang creates relies on elaborate construction based on science. (Same thing happens with Exhalation.) With a take on religions and their logical loopholes that I particularly enjoy, like Hell is the Absence of God, where the central character is no given the choice of Pascal’s wager. And the nonsense of attributing handicaps and hardships to dog’s testing impacted individuals, as well as the involuntary humour in the innocent casualties resulting from angels visiting Earth.  Some stories I liked less, like Understand, about a superhuman emerging from drug tests since the end cannot keep up with the premises. But others I really appreciated, from Babel, set in a naïve (very medieval) version of the World, with a flat Earth and a solid sky. To Division by Zero, where a Gödelian mathematician pushes the impossibility theorem to ruin all of mathematics, and to the superb Seventy Two Letters, that mixes cybernetics, Kabbalists’ golem, genetics and eugenics, in a Victorian setting that could make it pass for a steampunk story, but I disagree with this label since the novella somewhat runs backwards by returning to a freedom of choice that trumps eugenic goals, while aligned with the Victorian perception of science. The same with Story of Your Life, about constructing communication channels with a perplexing if peaceful alien race, whose purpose for this attempt is never clear, which is not an issue with enjoying the built-up of an understanding, as well as the disrupted time-frame of the narration. Or even the short (Nature) story, The Evolution of Human Science, which reflects the very real concern that AI could take over research, into directions that would escape human understanding (not a good signal for i!). Leaving hermeneutics (of AI research) to humans. And the final Liking what you see, a clever variation on the issues of “lookism”, the “burden” of beauty, and an imagined condition called calliagnosia that makes people insensitive to beauty or lack thereof in a person.

handbook of sharing confidential data [book review]

Posted in Statistics with tags , , , , , , , , , , , , , on March 12, 2025 by xi'an

A new Chapman & Hall handbook appeared on the most current issue of confidentiality and privacy, which has been edited by Jörg Drechsler, Daniel Kifer, Jerome Reiter, and Aleksandra Slavković. The forty authors of the 18 chapters are mostly from the U.S., with a few outliers from Edinburgh (involved in two chapters on protecting the Scottish Longitudinal Study and the U.S. IRS tax data) and Tallinn (for a chapter on secure multi-party computation applications). This means a more U.S. centric focus for realistic implementations as, e.g., with the Census Bureau (which employs 25% of the authors), than those implied by EU regulations, for instance.

Overall, I enjoyed reading these chapters and would certainly use the book as a first entry to a graduate course on privacy (as opposed to some books I recently reviewed). The first two chapters are 100% formula-free and thus more surveys than informative entries to the field, imho. The following Part II on formal privacy techniques covers the expected standards of differential privacy, local vs. global design, single vs. multiple queries, consequence on learning machines and statistical procedures. Concerning Bayesian aspects, Chapter 7 about private machine learning has two paragraphs on the privacy properties of MCMC algorithms albeit not exposing clearly enough that privacy vanishes as the number of iterations grows to infinity. Chapter 8 concentrates on statistical differential privacy, much along my own perception of the requirements for a genuine statistical approach, with Bayesian aspects not sidelined. If less critical of differential privacy than I. Chapter 9 focusses on system issues, investing a dozen pages into the specifics of pseudo-random generators. Part III is about synthetic data, with some overlap between the first two chapters. (I would deem DP need not be introduced by Chapter 12.) I find the section rather superficial, mostly formula free, and lacking in the statistical impact.

As an aside, I am disappointed at the poor rendering of (mathematical) equations making me wonder which type of LaTeX, if any, was used. There are even genuine typos  that seem to result from cut and past encoding errors (see, e.g., the final accentuated c of Sklavković). The reference lists are plentiful, see e.g. the 164 entries for Chapter 7, to the point it would have made more sense to regroup them into a single bibliography. (The predictable reply being that chapters are sold separately and need their respective reference lists.)

[Disclaimer about potential self-plagiarism: this post or an edited version of it could possibly appear in my Books Review section in CHANCE.]