Prospect hunting: The meaning of a Junior Grand Slam title

Who's next?

It's one of the central questions that defines sports. In team sports, every franchise devotes a significant portion of its resources to scouting, acquiring, and developing the next generation of stars. Fans are far from immune to the allure of this question, as the NFL and NBA drafts are subject to considerable speculation even years in advance (a Google search for 2018 NFL Mock Draft, analysis of an event that is over two years away, returns nearly 100,000 results, with just over 90,000 for the NBA). The draft is somewhat less-publicized in baseball (though I believe it's still televised on the MLB Network), but several popular websites (such as Baseball America) are completely dedicated to scouting and projecting amateur and minor league players.

This side of sports becomes trickier when you look at individual competitions, such as tennis. Outside of national tennis federations (which are not fully cohesive competitive units), there are no teams searching for the next big thing, so curious fans of the sport are left on their own in seeking out prospects to a much greater extent than they are in football or basketball.

That's not to say that the fans are completely without resources; information about the Challenger, Futures, and Junior tours can easily be found on the ATP and ITF websites, and the ITF even publishes junior rankings. But following the ATP World Tour itself takes a good bit of time, and most fans will direct their attention where it has the best chance of paying off - watching the major events and waiting for young players to produce results there.

There is one simple compromise that can be struck between focusing on the biggest events in tennis and keeping an eye on young players: the Junior Grand Slams. Held during the second week of each Slam (once the mens' and womens' singles and doubles draws are winnowed down and therefore take up fewer courts), the Junior Slams offer young players a chance to compete against their peers on a stage that's at least adjacent to the most important courts in the sport. And for the fans, moving from the main singles draw on the Slam's website to a junior singles draw requires just two clicks of a mouse.

The question then becomes: Is this an effective way of finding future tennis stars? What does it mean for a player to win a Junior Grand Slam title?

Let's find out.

The Junior Slams were first held in 1973, and have continued uninterrupted since that time. The 2016 Australian Open was the 173rd Junior Slam completed. These events have been won by a total of 138 different players. We'll be looking at these players in terms of a few fairly simple measurements: career high ATP ranking, matches won, titles, and Grand Slams won.

Career high ranking: The median Junior Slam champion (to be abbreviated as JSC for my own sanity) has a career high ranking of 50.5, which means that as of this writing, exactly half of them have broken into the top 50 at some point in their careers. (Andrey Kuznetsov and Alexander Zverev are sitting just shy of 50 right now waiting to mess this up, so I'd better get this posted before they do.) 50 of the 138 have spent time in the top 25, and 28 (about 20%) have been in the top 10. On the other hand, 49 of them have yet to appear in the top 100 (down from 50 as of this month, thanks to Taylor Harry Fritz), and 25 have not appeared in the top 200. (Some of this is skewed by the players who've recently joined the list and haven't fully embarked on their professional careers yet - but 16 of the 25 players who have CHRs below 200 are no longer active, and some of the others are still playing but have fallen well below their career bests.)

Match wins: The median number of ATP-level match wins for a JSC is 65.5. 57 of the 138 have at least 100, 44 are over 200, and 26 have exceeded 300 (with Marcos Baghdatis sitting a good week away from making it 27). On the other hand, about 40% of the players on the list (52) have less than 20 career World Tour level victories, and 17 of them (nine of whom are no longer playing) have none at all as yet.

Titles: Almost exactly half of JSCs have won a title at the ATP level, 68 of the 138 (most recently Nick Kyrgios, who claimed his first within the last month). A further 10 have made at least one final but have yet to capture a title. (Five of those ten are still active, and two of them reached their first finals this year and have not yet turned 20, so they have good chances of eventually joining the title-winning set.) 31 of the players listed have won at least 5 titles, 17 have at least 10, and seven have 30 or more.

Slams: Ten JSCs have gone on to win at least one Grand Slam; seven have more than one, and they have won 52 Slams total between them. The first of these was John McEnroe's 1979 US Open title; from that point on, they have snapped up 52 of the 146 Slams that have been played, which is a very respectable 36%.

So, the median JSC has at least a respectable career - double-digit match wins and even odds of grabbing at least one title. Can we break things down further than that? Do you even need to ask?

There are fewer winners than Slams played, so there must be at least a few players who've won more than one Slam, right? (It's not a trick question. There are.)

The 26 players who've won multiple Junior Slams have been significantly more successful as a group than their single-title counterparts:

Multi-JSC winners (26 players):
Median CHR 22.5
Median wins 181
20 players with at least one title
9 top-10 players
4 Grand Slam champions (16 Slams won)

Single-JSC winners (112 players):
Median CHR 67
Median wins 37
48 players with at least one title
19 top-10 players
6 Grand Slam champions (36 Slams won)

Unsurprisingly, a second Junior Slam title (or more) appears to be a very promising sign.

Among single JSCs, the obvious next step is breaking things down based on which Slam they won. The results there are... illuminating:

French Open (32 players):

Median CHR 23

Median wins 130

18 players with at least one title

10 top-10 players
4 Grand Slam champions (17 Slams won)

US Open (27 players):

Median CHR 28

Median wins 71

16 players with at least one title

4 top-10 players
1 Grand Slam champion (2 Slams won)

Wimbledon (25 players):

Median CHR 71

Median wins 24

8 players with at least one title

3 top-10 players
1 Grand Slam champion (17 Slams won... who could that be?)

Australian Open (28 players):

Median CHR 136.5

Median wins 6

6 players with at least one title

2 top-10 players
No Grand Slam champions

A JSC who wins the French Open only has generally been nearly as good as a multiple-JSC, and the US Open is only a slightly less-promising sign. Winning a single Junior Australian Open, meanwhile, has been nearly meaningless in the past in terms of predicting future success, and one Junior Wimbledon isn't much better (Roger Federer aside). If I were to speculate on the reasons for the differences, I would guess that the Australian suffers for the same reason the grown-up version of the event had issues in the late '70s and early '80s: it's a pain to travel there and it's not worth the trouble or the expense for some of the top players, so the fields (and therefore the champions) are weaker. Wimbledon, meanwhile, may not be as useful a predictor because it's played on grass, a surface on which few young players will have any notable experience, and on which not many tournaments are played by the pros outside of the Fortnight.

Those numbers give an idea of how to read Junior Slam results - but how relevant are they today? The sport has changed quite a bit since Paul McNamee won the Junior Australian Open in 1973, and it's not entirely clear whether his 246-win, two-title career means much in terms of projecting Oliver Anderson, his 2016 counterpart.

Let's do one more breakdown, this one by era. We have 44 years' worth (well, really 43 and a quarter) of Junior Slams to look at, so we'll split it into 11-year segments and see if we can detect any changes. Players will be grouped by the year in which they won their last Junior Slam.

1973-83 (30 players):

Median CHR 30.5

Median wins 98

19 players with at least one title

7 top-10 players
4 Grand Slam champions (23 Slams won)

Best players: Ivan Lendl, John McEnroe, Mats Wilander

Multi-JSCs: 8 (including Lendl); 7 of them had CHR of 35 or better and at least 106 wins

1984-94 (35 players):

Median CHR 51

Median wins 99

20 players with at least one title

5 top-10 players
1 Grand Slam champion (6 Slams won)

Best players: Stefan Edberg, Marcelo Rios, Thomas Enqvist

Multi-JSCs: 8 (including Edberg); 5 of them had CHR 32 or better, and all 8 had at least 59 wins

1995-2005 (36 players):

Median CHR 23

Median wins 210

23 players with at least one title

15 top-10 players
5 Grand Slam champions (23 Slams won)

Best players: Roger Federer, Andy Murray, Andy Roddick

Multi-JSCs: 5 (including Roddick); 4 reached the top 10 and won over 300 matches

2006-16 (37 players):

Median CHR 145

Median wins 5

6 players with at least one title

One top-10 player
No Grand Slam champions

Best players so far: Grigor Dimitrov, Bernard Tomic
Best prospects (arguably): Nick Kyrgios, Borna Coric, Alexander Zverev, Taylor Harry Fritz

Multi-JSCs: 5 (including Dimitrov and Tomic); three have reached the top 50 and have at least 80 match wins to date

Now, there is obviously a huge bias in the numbers for the last group; the aforementioned Oliver Anderson currently has a career high ranking of 649 and zero ATP match wins, but he also doesn't turn 18 until April, so he has some time to change that. But even if you cut it down to JSCs from 2006-10, leaving you with players who've had at least 5 years to establish themselves professionally, you still get only half of them (9/18) having spent time in the top 100, and just a third of them having reached so much as a single final.

The current group of promising young players is heavily populated with JSCs (all four of the "best prospects" listed above are 20 or younger, are in the current ATP top 80, and have won multiple Challenger titles; three have already reached at least one final, and the other has made several semis). So until we see how their careers develop, it's premature to definitively claim that junior laurels have completely lost their power to predict professional success. But the early results suggest that Junior Slams may not be quite the indicator of future stardom that they once were.

With that caveat in mind, however, the Junior Slams have a history of identifying players with strong chances for excellent professional careers, especially if you focus on the players who win more than one, or those who win the French and US Opens. Given the simplicity of tracking the junior draw during the second week of a Grand Slam, when a fan of the sport is probably following tennis pretty closely anyway, the events are a highly worthwhile investment of a tennis enthusiast's time.