Archive for placebo effect

against method

Posted in Books, Statistics, University life with tags , , , , , , , , , on March 29, 2020 by xi'an

A vitriolic tribune in Le Monde this weekend by the microbologist Didier Raoult, head of the Institut Hospitalo-Universitaire Méditerranée Marseille, campaining for the immediate use of the hydroxychloroquine sulfate drug for coronavirus patients. Arguing that the major emergency of the coronavirus pandemic calls for this use without waiting for confirmation from clinical trials, without controlled comparison with other drugs or a placebo. Solely a study of patients being administered the drug, outside the usual practice of clinical trials.

“Enfin, l’envahissement des méthodologistes amène à avoir des reflexions purement mathématiques.” [At last, the invasion of methodologists leads to purely mathematical reasonings.]

“Ce modèle, qui a nourri une quantité de méthodologistes, est devenu une dictature morale.” [This model, which has fed quantity of methodologists, has become a moral dictatorship.]

“…il faut nous débarasser des mathématiciens, des metéorologistes [sic] dans ce domaine.” [we must get rid of mathematicians and meteorologists in this domain]

“…conseil scientifique dans lequel on trouvait deux modélisateurs de l’avenir (qui pour moi représentent l’équivalent de l’astrologie), des maniaques de la méthodologie. Les médecins confrontés au problème du soin représentaient une minorité qui n’avait pas nécessairement l’habitude de s’exprimer et qui se trouvait noyée par cet habillage pseudo-scientifique.” […scientific committee including two modelisators of the future (equivalent in my opinion to astrologers), manics of methodology. Physicians facing treatment problems were a minority not necessarily used to intervene, overwhelmed by this pseudo-scientific babbling.]

Obviously I have no expertise in drug development or even in epidemiology, but the name-calling tone of this tribune, as illustrated by the above quotes, is appalling and populist, more in the spirit of Trump than of a rational search for scientific evidence. On the opposite, the arguments therein are a-scientific and reject the use of mathematical and statistical methodology for being… mathematical. And resort to name-calling, while not considering the more than philosophical aspect that opting for this drug rather than another one may be reducing survival chances for some groups of patients. (While the title chosen for this post reflects the title of Raoult’s tribune, with its philosophical pretenses, let me stress that Feyerabend’s book is not mentioned therein and that the article contains no indication that the author relates to Feyerabend’s views.)

statistics in Nature [a tale of the two Steves]

Posted in Books, pictures, Statistics with tags , , , , , , , , , on January 15, 2019 by xi'an

In the 29 November issue of Nature, Stephen Senn (formerly at Glasgow) wrote an article about the pitfalls of personalized medicine, for the statistics behind the reasoning are flawed.

“What I take issue with is the de facto assumption that the differential response to a drug is consistent for each individual, predictable and based on some stable property, such as a yet-to-be-discovered genetic variant.”S. Senn

One (striking) reason being that the studies rest on a sort of low-level determinism that does not account for many sources of variability. Over-confidence in causality results. Stephen argues that improvement lies in insisting on repeated experiments on the same subjects (with an increased challenge in modelling since this requires longitudinal models with dependent observations). And to “drop the use of dichotomies”, favouring instead continuous modeling of measurements.

And in the 6 December issue, Steven Goodman calls (in the World view tribune) for probability statements to be attached as confidence indices to scientific claims. That he takes great pain to distinguish from p-values and links with Bayesian analysis. (Bayesian analysis that Stephen regularly objects to.) While I applaud the call, I am quite pessimistic about the follow-up it will generate, the primary reply being that posterior probabilities can be manipulated as well as p-values. And that Bayesian probabilities are not “real” probabilities (dixit Don Fraser or Deborah Mayo).