Gavarret LDJ (1840)

Principes généraux de statistique médicale: ou développement des régles qui doivent présider à son emploi [General principles of medical statistics: or the development of rules that must govern their use]. Paris: Bechet jeune & Labé.
In 1840, the French physician and statistician Jules Gavarret published a book on statistical analysis of treatment tests, stressing the importance of estimating uncertainty and calculating ‘limits of oscillation’ associated with estimates of treatment effects.

Title page(s)


Key passage(s)



“If we now take a quick look at all of the considerations we have developed in the course of this work and endeavour to summarize them in as few words as possible, we are led to put forth the following propositions as having been absolutely demonstrated.”



“The rules of logic are inadequate for judging the influence of a given medication in an equally given disease and for classifying the medications recommended for this same disease according to their influences.”



“The principles of the law of large numbers are strictly applicable to therapeutic research and they alone can furnish the solution of these two important problems.”



“Average mortality, as provided by statistics, is never the exact and strict translation of the influence of the test medication but approaches it all the more as the number of observations increases.”



“A therapeutic law ensuing from the comparison of a small number of observations may be so far from the truth that it merits no degree of confidence in any case whatsoever.”



“A therapeutic law can never be absolute; its applications can always oscillate between certain limits which are all the narrower, the more the collected observations are multiplied, and which can be determined with the aid of the numbers constituting the statistics that have provided the law.”



“To be able to decide in favour of one treatment method over another, it is not enough for the method to yield better results; the difference found must also exceed a certain limit, the extent of which is a function of the number of observations.”



“Any difference in the results obtained that is below this limit, while this limit decreases as the number of observations increases, must be disregarded and deemed void.”



“The same principles and the same inferences strictly apply to the solution of the basic difficulties arising from the doctrine of the medical constitutions.”



“By applying the same rules, one must endeavour to ascertain whether the mortality rate of a disease changes according to age, sex, regions, etc., etc.”



“Whenever aetiology is uncertain, the principles of the law of large numbers can only serve to prove the existence or non-existence of a suspected specific cause, regardless of any hypothesis as to its nature. One must try to determine the cause itself [on the basis of] considerations of another kind; this last concern is outside the domain of statistics.”

Translation by Ulrich Tröhler


 Louis Denis Jules Gavarret (1809-1890)


Key articles

  • Huth EJ (2005).
    Quantitative evidence for judgments on the efficacy of inoculation for the prevention of smallpox: England and New England in the 1700s.
  • Huth EJ (2006).
    Jules Gavarret’s Principes Généraux de Statistique Médicale: a pioneering text on the statistical analysis of the results of treatments.
  • Huth EJ (2006).
    Transatlantic ideas on the philosophy of therapeutics in the middle of the 19th century.


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