In March 2009, the Spanish Directorate General of Traffic made the following announcement in the media: 22% of those who died in traffic accidents were not wearing seat belts. To save lives, everyone is recommended to use them.
Expressed in this way, the data are ambiguous. One might argue in this way: if just 22% of the victims were not wearing the seat belt, then a number over three times larger (78%) were in fact wearing seat belts when they died in an accident. Therefore it looks like it would better not to use the seat belt at all.
I’ll explain why this conclusion is fallacious. In order to draw the correct conclusion out of the data, one fact is missing: with or without accidents, how many people do use the seat belt and how many don’t? This piece of data can be found, although it took me some time and effort: 95% drivers do wear the seat belt, just 5% don’t. Combining this with the original data, we can compute the probability of dying in an accident with and without the seat belts: it is over 4 times higher among those who do not wear it than among those who do. If everybody used it, the number of deaths could decrease by 18%. Therefore the advice given was sound, although the data were incomplete.
Given how this news was presented, I feel moved to complain about the way in which politicians and the media use statistics and incorrectly report scientific data. If I do that, am I doing politics? Or am I defending science?
In 1897, in the USA, the Indiana House of Representatives approved (by 67 votes against none) Bill #246, which stated that the value of pi in that state would be equal to 3.2 (it said literally “that the ratio of the diameter and circumference is as five-fourths to four,” i.e. 1 divided by pi = 5/4 divided by 4 = 1 / 3.2, ergo pi = 3.2). The project went to the Senate, where it was not even presented, due to the active opposition of Clarence Abiathar Waldo, professor of mathematics at Purdue. Was Professor Waldo doing politics when he opposed a bill that had been passed unanimously? Or was he doing science?
When scientists fight for their right to conscientious objection, when they refuse to work in the production of poisonous gases, anti-personnel mines or nuclear weapons, or to perform experiments on human beings without their consent, are they doing politics? Shouldn’t there be an ethical dimension of science?When supporters of abortion resort to anti-scientific statements, such as that the embryo is not a human being, or that the embryo is a part of the body of the mother, or that the embryo is just a collection of cells (what are then the adults?), if scientists claim that these statements are false and defend the right of physicians to conscientious objection, are they doing politics? Or are they doing science?
The same post in Spanish
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