If you have chosen a sufficiently large sample, you will notice that the probability that the date of birth of the selected players is close to January is quite high.

In fact, if we visualize the birthday month of all the Serie A players of the 23-24 season, we can notice an evident shift towards January, accentuated by what looks like a real decreasing trend between player counts versus birth months.

It might seem like a coincidence, but if we extend the analysis to the 5 most important football leagues in Europe, it turns out that the situation doesn't change that much. In fact, if we divide the year into 3 quadrimester and count the number of births for each of them, we realize that the law remains surprisingly inviolate.

"Footballers who play at a high level are mainly born toward January".

And far more surprising is that none of these leagues have players born in the majority in the last 4-month period.

If you still think it might be a case, we can try for sake of diligence to also visualize some other player parameters such as height, weight or age. From what we can see below, these show no significant patterns and have, as might be expected, the classic bell shape typical of a normal distribution.

In practice, in a group of soccer players there will always be those who are taller, thinner or older, but generally most of them will present characteristics that are "average" and normal, with the exception of the month of birth which is affected evidently by some kind of suspicious influence.

This influence is a direct consequence of what is called The Matthew Principle. And here again, as in the case of the nascent of the interview, a multi-level reasoning needs to be done.

To understand Matthew's principle fully, let's take as reference the story of two people born on January 1st and December 31st of the year 2000 respectively.

As you will have understood, the further you go back in time, the more the difference between the relative age of two peers increases and this growing delta results into a series of small marginal benefits in everyday life.

These small advantages generated at an early age, accumulating, can transform into gradually larger advantages in adulthood, triggering a compounded effect that can be visually represented in the following way

In the period between birth and adolescence, the child born on January 1st had 11 more months to grow, which made him taller, stronger and faster. The consequence is that the greatest, thanks to his physical growth, will have greater possibilities to be selected by the coach to play. By playing more he has a better chance of improving. By improving more quickly, he has a greater chance of being noticed earlier by talent scouts and so on... nurturing what is indeed a vicious cycle, where the line between a player's talent and the advantage he accumulates as a function of his age, blurs behind overly anticipated coach decisions and prophecies that then end up being self-fulfilling.

The phenomenon that triggers this problem associated with relative age is known specifically as the Matthew Effect, which in its financial interpretation states that "The rich become richer, the poor poorer".

This principle is not only applicable to football, but to any high-level sport and to many other social areas where competition plays a fundamental role.

One would be inclined to think, why not break this kind of social pattern and adjust conventions when necessary to give everyone an equal chance of success? Obviously this is not such an easy issue to handle, and so much could already be done just by making youth coaches aware of this phenomenon, data in mind.

But one last point still remains open, which alone could partially justify maintaining the status quo and somehow enhance this sort of "casual injustice”. As often happens in nature, there is in fact a self-regulation mechanism that produces effects that in a situation of equilibrium may never appear.

Let's take for example these 3 players who were born in the months near the end of the year.

The players in question are undoubtedly among the most awarded footballers ever and are recognized by all, experts and non-experts alike, for their undisputed football qualities. This is because being born early means having a greater chance of being selected to play when young, But the "performance" thing then is a story in itself.

In fact, there are those who hypothesize, in contrast to the Matthew effect, the scenario of Underdog payback, in which smaller and physically less mature children develop a set of superior skill sets that allow them to emerge in highly competitive situations. And taking the players mentioned above as a reference, it is not difficult to believe in this theory.

After all, it is often the adverse conditions that delineate the hallmarks of the champion, capable of breaking the conventions that have been more or less implicitly inculcated in us, demonstrating that statistics can be overturned and fate can be written through one's actions.