Do Semi-Finals Matter? A Look at the Data

By Braden Keith on SwimSwam

Do Semi-finals matter?

Semi-finals in swimming are a controversial topic. There are basically three schools of thought on the topic.

One school is that they are a waste of time and energy, they make meets longer, and they don’t really change the final outcomes.

Another points out that maybe the “challenge” we’re trying to create and the “best of” standard is “who is the best in the third of three rounds, spread over two days”. This could be coupled with “the sessions can’t become any more compact because of doubles anyway.”

A third school of thought is less-stated and more-often implied, but basically would be the ‘null’ state: that semi-finals are an important step toward determining the final 8 field with the top swimmers racing as close to head-to-head as possible for that opportunity.

Other race sports often use semi-finals. In some sports, like track & field or rowing, the top performers in the heats get a free pass to finals, whereas the next-best group might have to compete in a repechage for a chance at the medals.

But swimming, frankly, doesn’t have as much parity of many of those sports, and it would be a pretty radical change (one that wouldn’t go over well) to force some swimmers to race an extra round and not others – which could push bigger gaps into the idea of parity.

Some of this stuff cannot be solved with data, but to frame the conversation, I asked SwimSwam’s Daniel Takata, who runs the @swimmingstats Instagram account, to look at how many medalists (and gold medalists) finished outside of the top 8 in prelims.

Acknowledged: applying data from meets where there are semi-finals is not a perfect surrogate for meets where there aren’t semi-finals. Swimmers would approach races differently. That makes the analysis incomplete-by-definition, but not without value.

Doubly acknowledged: medals aren’t the only goal of swim meets.

Since semi-finals in the 50m, 100m, and 200m events were re-introduced at the 2000 Summer Olympics, there have been 1,391 medals distributed in those events at the Olympic Games and World Aquatics Championships.

Only 120 of those 1,391 medals (8.6%) placed outside of the top 8 in prelims.

If we drill down to gold medals (463 since 2000), 20 finished outside of the top 8 in prelims (4.3%).

This means that even with an incentive structure that doesn’t require a full-effort prelims swim from a top performer (threading that needle is a valuable skill on its own), switching from a semi-finals system to a straight prelims-finals system has some impact, but not immense impact.

At more recent meets, here are the medal numbers:

2021 Olympics: 1/60 medals (only Japan’s Yui Ohashi in the women’s 200 IM, which she won)
2022 Worlds: 7/79 (8.9%)
2023 Worlds: 8/79 (10.1%)
2024 Worlds: 6/78 (7.7%)

This 7-10% range seems to be pretty consistent across the board.

In other words: the data is inconclusive. This number is neither low enough to fully wave it away nor high enough to declare a definitive sorting value to the semi-finals.

Because of the nature of swimming, it would be impractical (if not impossible) to test the influence of semi-finals on prelims effort in any empirical way.

My take? I’d love it if we could cut out semi-finals to find a way to trim the meet back to a 7 or 8 day event. I think that anything shorter than that winds up with some unintended consequences. Maybe leaving semi-finals in for 50m and 100m races, but dropping them for 200m races, would be the compromise, because the gaps from the medalists to the non-finalists in 200 meter races would be significant.

But amid the constant tug-of-war whereas we debate whether swim meets should be viewed as spectator events or base-development events, dropping semi-finals could dissuade some countries from investing as much in the sport (it’s easier to spend tax dollars on sports when citizens can cheer for athletes in prime time). It also adds some storylines to the game, gives fans more things to be fans about.

At a minimum, it would allow athletes to compete on the biggest stages the same way that they compete the rest of the year (it’s very rare even for Olympic Trials to employ semi-finals).

Whatever the system, the athletes and coaches and training would inevitably adjust, and in a few decades, the thing that once felt new would again become norm.

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