I came across a great article - Are first-borns more likely to attend Harvard? - in the recent issue of Significance. Antony Millner and Raphael Calel investigates Michael J. Sandel’s famous “experiment” in the light of statistics.
In his book, Justice: What’s the Right Thing to Do, Sandel argues against Rawls difference principle. The principle in nutshell : “The difference principle permits inequalities in the distribution of goods only if those inequalities benefit the worst-off members of society. Rawls believes that this principle would be a rational choice for the representatives in the original position[…]” (read the full article on PoliticalPhilosophy.Info) One possible argument against the principle is “it neglects the casual relationship between effort and achievement” as Millner and Calel summarize it. Sandel runs a short poll on who is first-born in the auditorium during his lectures at Harvard (you can watch the whole course “Justice with Michael Sandel” online). You can see the poll and the possible arguments against Rawls’ principle from about 22:00 in this video.
After the poll, Sandel concludes that 75-80% of the students are first-borns and this is in-line with some psychological research. But according to the Significance article Sandel makes a base-rate fallacy and forgets the fact that “wealthy and well-educated parents tend to have fewer children” and those children are over-represented in Harvard’s student population.
I think philosophers should be more precise when they use examples. But this doesn’t undermine the questions raised by Sandel. Philosophy is about asking questions and engaging in discussions (with the other contemporaries or with the history of philosophy), hopefully Sandel finds a new example next semester.