Basketball Evolution: 3-point shot evolution in Serie A

Welcome back to Hack a Stat! For the Basketball Evolution, I would like to see how the 3-point shot in the Serie A has changed.



Today’s 3-point shot is a must for every team, whether it plays in the NBA, Serie A or Euroleague, even if, as we know, it has not always been this way. The 3-point shot was introduced in Italy in the 1980s precisely in the 1984-1985 season; initially, the use of this shot was really low and exclusive of players in spots 1, 2 and, more rarely, 3. I guess at the time seeing a forward or a center shot from outside the area was already strange, so seeing them outside the 3-point arc was impossible.

Slowly, however, the 3-point shot starts to take hold. It begins to become an additional weapon, an important strategic element in the game economy, up to the present day, where it is an essential factor of the game.

This analysis has been performed on the Italian championship but the reasons found and the conclusions are valid for all European and American basketball. There will probably be some differences in the values, but the trends found are the same.

3-point shot evolution

The 3-point shot evolution can be seen from the chart below, which shows the shots attempted per 100 possession by all the teams over the past 30 seasons:

From the 1987-1988 season, the Lega Basket website offers the boxscores of the teams and all the players, divided by the 3 main roles, guards, forwards, and centers. The previous seasons, unfortunately, don’t have this option.
That said, let’s move on to the elaboration: during the seasons examined the championships were played with different numbers of teams and consequently of games played. I then normalized the total number of shots attempted by all the teams by referring to a championship consisting of 16 teams and 30 games played. The values obtained from this normalization have been redistributed over 100 possessions, to overcome the pace differences among the various seasons.

As can be seen, the 1980s was the 2-point shot era; another great source of points were the free throws. Just under 15 shots per 100 possessions were attempted from beyond the arc: the 3-point shot was introduced three years ago and its use was still not widespread. However, as it is easy to notice, 3-point shots attempted per 100 possessions have increased every season: a steady and quite fast growth. The 2016/2017 season highlights how the shots attempted from the 3-point area after 30 years have doubled! On the other hand, the 2-point shots have drastically decreased; free throws also fell, but certainly less than 2-point shots.

Reasons for the raising

Clearly, however, this chart does not show anything shocking: we all know that today teams shot a lot of 3-point compared to the past and the chart does nothing but confirm it; what should interest us most is the growth rate over time. It is not uncommon to hear that in the last few seasons the 3-point shot has been abused compared to the recent past (8-10 years ago). Here, the chart instead shows how the real surge occurred between the introduction of the shot up to the seasons 2002/03 and 2003/04: it went from 15 shots to 25 shots per 100 possessions in 17/18 years. Since then, usage has always increased, but growth has been slower. These two seasons just mentioned are in fact a critical point of the change of playstyle; until this moment precise trends can be seen:

  1. Strong increase of 3-point shots;
  2. Strong decrease of 2-point shots;
  3. Number of free throws attempted remains the same;

And after that moment:

  1. Increase of 3-point shots;
  2. Number of 2-point shots remains the same;
  3. Decrease of free throws;

This is a detail that intrigued me. In those seasons there were no particular rules changes that could have turned that trend. To find a possible reason for this change we need to look at the next chart:

3 point shot evolution

This histogram shows the 3-point shots attempted per 100 possessions, always normalized on a 30 game played championship and considering a sample of 50 players per role. Made 100 the sum of 3 shots attempted in each season, I divided them according to who shot them: guards, forwards and centers. We can thus see how in the 80s and 90s, most of the shots attempted from beyond the arc were taken by guards, while about a third from the forwards; the centers shot less than 6/7% of the total triples attempted. However, around the 2000s something changed: already in the 2001/02 season, there was a marked increase in the 3 shots attempted by the centers. From that moment on, the centers have never fallen below 13%. This is one of the reasons for that trend change that we found in the previous chart: in those years, Italians played centers such as Garbajose, Tusek, Smodis, players who can shot from beyond the arc. In short, the atypical centers were spreading in our championship; centers that were not limited to playing in the area, but were dangerous even beyond the arc.

In short, in those years it started the evolution of the game that led to today’s basketball, made of very wide spacing in which the 3-point shot is an essential weapon to spread the defense and makes the area empty.

The more consistent presence of centers and forwards outside the arc also explains the collapse of the free throws and the stabilization of the 2-point shots: having fewer post-ups, less foul situations occurred. In the 80s and 90s basketball, a good part of the points of centers and forwards came from the free throw line: being less present in the area, the fouls drawn were less. Similar speech for the guards, who in a less crowded area suffered less contact and therefore fewer fouls.

As for the stabilization of the 2-point shots, it is clear that a freer area has allowed guards greater drive chances and therefore of 2-point baskets.

Shooting distribution by roles

What has just been explained is not only a guess, but it is all evident through the following charts. We observe the trend of shots attempted per 100 possessions by guards, forwards, and centers over the past 30 seasons.

3 point shot evolution
3 point shot evolution
3 point shot evolution

The three charts confirm the stabilization of the 2-point shots after the seasons 2002-03 and 2003-04; the slowdown of the decrease of this shot for the guards is the most evident, precisely because of the spacing. Similar speech for the small forwards.
For the centers, on the other hand, the decrease in 2-point shots is less marked but still present due to the increase in 3-point shots.

As for free throws, the guards and forwards have had the greatest decrease: the centers have maintained the number of free throws attempted over time, even if a small reduction can still be noticed.

In conclusion, the use of the 3-point shot has really grown since its birth and, above all, it is no longer the prerogative of the guards, but now it has become an important weapon also for the big men.

This post ends here. See you soon, your friendly neighborhood Cappe!

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