Degrees of Dominance (with Peaty, Ledecky, and Sjostrom)

Courtesy of Barry Revzin, resident SwimSwam stat-fiend.

Watching Adam Peaty swim breaststroke, Katie Ledecky swim distance, or Sarah Sjotrom sprint fly, you can’t help but be amazed at just how far ahead of the rest of the world they are. Their dominance is at this point a foregone conclusion – they are racing the clock, the rest of the field is racing for silver. But while they may not have another competitor in the pool, I thought it might be interesting to take a look at a different kind of competition: history.

I took a look at the margin of victory in every Olympic and LC World Championship final from 1986 to the present. I picked 1986 to be after both boycotted Olympics and the GDR drug era, but also because I happened to be born in that year. In order to compare races of different distances, I used percentage gaps. To give a sense as to how percentages correspond to the most recent races:

• 0.3% is a close but visibly clear win, like Chad le Clos in the 200 fly (0.34%) and Federica Pellegrini in the 200 free (0.39%).
• 1% is a convincing win, like Sun Yang in the 400 free (1.10%) and Sarah Sjostrom in the 100 fly (1.16%).
• 1.5% is pretty dominant, a bar that Lilly King’s 100 breast victory approaches (1.39%)
• 2% is basically a race for second place. This is where Adam Peaty in both the 50 (2.00%) and 100 (2.25%) breaststrokes, and Katie Ledecky in the mile (2.01%).

The overall distribution of percentage margin of victory looks like:

Close wins are pretty common, and there is a pretty steep, rapid drop off. About one in four races had a margin as high as 1%, only about one in ten hit 1.5%, only one in forty hit 2%.

What about those blips at the far end of the graph? How dominant have the historically dominant wins been? The top 10 margins of victory over the last 31 years, to date, are:

Pretty interesting list! Leisel Jones twice in the top 10. Michael Phelps three times in the top 10 (granted, twice as the winner, and the third time as the distant silver-medalist to Crocker’s then-world record swim in Montreal). Surprisingly, despite Ledecky’s regular dominance, she hasn’t quite cut the top ten. Her largest margin of victory, the 800 free at the Rio Olympics, was “just” 2.3%, 15th on the list.

Adam Peaty came pretty close this week to getting himself another entry in the top ten. After the semifinals of the 50 breast, he was seeded a whopping 2.74% ahead of Felipe Lima. He still won by 2%, but will have to wait until the next meet to crack this list. Even Ledecky’s mile, where she was so far ahead that for a while the camera crew just gave up on her and starting showing the race for second instead, even that swim just wasn’t a big enough win.

There are two more races in Budapest that have a chance of rewriting this leaderboard, and both will take place on Saturday:

1. The women’s 800. Ledecky is seeded 2.3% ahead of hometown favorite Boglarka Kapas. This will be Ledecky’s last swim of a long meet, and she is the prohibitive favorite for the gold. But how prohibitive?
2. The women’s 50 fly. As amazing as Ledecky and Peaty have been in their respective spheres, when it comes to the 50 fly, Sarah Sjostrom is practically a video game. Sjostrom is seeded 24.76 (a time that would have finished 3rd at US Trials in the 50 free). The second seed, Japan’s Rikako Ikee, is all the way back at 25.51. That’s a margin of 2.94%. But, as absurd as it may seem to say, 24.76 seems like a very conservative. After nearly breaking her own world record in the 100 fly and obliterating the world record in the 100 free, it seems like a better than average bet that she would approach her world record of 24.43, set back in 2014. If she does so, that puts her well over 4% ahead of Ikee.

I, for one, can’t wait to see what happens.