The other day, as I was watching a random Miami match, I wondered aloud on Twitter about how interesting it would be if we could get a statistic that tells you what percentage of forehands hit in a match don’t result in unforced errors. Simple idea, no? As we know, the ATP MatchFacts don’t give you any info on forehands and backhands. And just since Indian Wells does TennisTV give you a number for forehand unforced errors and one for backhand unforced errors. We do know that Hawk-Eye can tell how many forehands and backhands a player hits during a match, but I have no access to that data. Hence, why not count forehands and backhands myself, and use the unforced error numbers that TennisTV gives me to come up with that stat I want?
I picked this morning’s match between David Ferrer and Kei Nishikori for this test. I focused on David Ferrer, since he’s a player we normally think hits a lot more forehands than backhands, and tends to commit few unforced errors. I counted how many forehands and backhands he hit during rallies (I chose not to count return of serves, but I think in the future I’ll count second serve returns, since the returner gets more time to hit that shot), and then came up with Ferrer’s Forehand Efficiency rating, which comes out of this formula:
(Total Attempted Forehands – Forehand Unforced Errors)/Total Attempted Forehands
The same would be true for Ferrer’s Backhand Efficiency Rating:
(Total Attempted Backhands – Backhand Unforced Errors)/Total Attempted Backhands
I counted forehands and backhands during each game, and wanted to create totals per set. I didn’t tally my own unforced error count, as I mentioned above, and took the TennisTV unforced error count at the end of each set.
With all of that in mind, let’s see what Ferrer’s Forehand and Backhand Efficiency Ratings look like for the first set, which the World Number 5 won 6-4. Here is my first set scorecard:
Some notes about that set: Ferrer served first, and the blue highlights on games 2 and 10 indicate that he broke Nishikori’s serve in that game, while the red highlight on game 9 means that Nishikori broke Ferrer’s serve. And here are the numbers from TennisTV:
So, according to our simple formulas from above, we can gather that in the first set, David Ferrer had a Forehand Efficiency Rating of 93.75%, and a Backhand Efficiency Rating of 88%. Those are pretty great numbers, no? This is why David Ferrer is a top 5 tennis player: he barely makes any mistakes. The hilarious part of that first set, of course, is that Nishikori actually had 6 fewer unforced errors than Ferrer, and still lost the set.
Now let’s move to the second set, which Ferrer won 6-2. Here is my scorecard:
Again, the blue highlight on games 4 and 8 mean that Ferrer broke Nishikori’s serve in those games. Here are the TennisTV numbers, which sadly aren’t segregated by set, so I will take out the 1st set numbers to come up with the 2nd set numbers:
The unforced error count for the second set would be: 2 forehand unforced errors and just a single backhand unforced error for David Ferrer. Thus, David Ferrer had a Forehand Efficiency Rating of 96%, and a Backhand Efficiency Rating of 97.8% in the second set.
How incredible is that? For the match, here are David Ferrer’s Efficiency Ratings:
Forehand Efficiency Rating: 94.9%
Backhand Efficiency Rating: 91.8%
That’s staggering. It simply means David Ferrer makes 5 forehand errors per 100 forehands attempted, and makes 8 backhand errors (the backhand being his weaker wing) per 100 attempts. This is incredible when we consider that this was a live M1000 match against a quality opponent.
Now…go back and look at my scorecards for sets 1 and 2. Do you spot a pattern?
Here, let me give you a hand. These are David Ferrer’s service games:
Do you see it? Here it is: Ferrer hit more forehands than backhands in every single service game. Here are Ferrer’s return games in that first set (remember, returns of serve were not included in this tally):
As you can see, Ferrer hit more backhands than forehands in 2 of those 5 return games. The trend is somewhat similar in the second set, where Ferrer hit more forehands in 3 of his 4 service games (in the remaining service game he hit as many forehands as backhands), and hit more backhands in 2 of the 4 return games (one of the four return games was also a tie between forehands and backhands). Why did this happen?
Because Nishikori was trying very hard to play to Ferrer’s backhand corner throughout the match, give how good his own two-hander is. You can see that serving would facilitate this plan, given that Ferrer’s returns would normally let Nishikori pick which side he wanted to hit to with the first groundstroke of the rally.
The Japanese Number 1 wisely tried as hard as he could to avoid forehand rallies, focused as he was on finding Ferrer’s backhand. And naturally, this was harder to do during Ferrer’s service games, since the Spaniard would almost always look to hit a forehand as his first shot after a serve, regardless of his position on the court. We know that Ferrer loves to run around his backhand and fire inside-out or inside-in forehands, and he tried to do that as much as he could today.
Finally, it’s interesting to see that David Ferrer hit just 5 more forehands than backhands in the first set, and the same applied to the second set. That’s minimal – the equivalent of a point or two.
Now, for some bonus nerdiness, here are some neat graphs from that match, courtesy of the broadcast:
No surprises here: everybody knows Ferrer doesn’t like to hit the backhand down the line all that much – even though Ferrer strangely tried to pretend otherwise during the Acapulco final.
Now, this is graph is fascinating. Look at how often Ferrer chances the direction of the ball with his forehand! And yet…Ferrer makes an error on only 5 out of 100 attempts with that shot.
Like I said above, that’s the kind of efficiency you need to make it into the top five.