when is the optimal strategy is to throw a badminton match?

I’ve been following the badminton scandal in the news. First, let me say that I never thought I’d hear the words “badminton” and “scandal” in the same sentence. I thought that this was one of those rare cheating events that sometimes happens. The evidence suggests that the optimal strategy may sometimes be to lose on purpose.

In previous Olympics, the entire set of badminton matches were in a tournament with knockout rounds. A team could apparently not chance their seed or path to gold. In this Olympics, there was a new preliminary pool round with the performance in the pool leading to seeds in the later single elimination tournament with 16 teams. This introduced a wrinkle to the optimal strategy. Now a team might want to think about how they could optimize their seed/path in the single elimination rounds. Obviously, introducing a path to the gold by doing something other than winning every possible match potentially invites trouble. However, the badminton rounds of play with a preliminary pool and later tournament is like what happens in volleyball, basketball, soccer, and other sports. I haven’t seen “lazy” players obviously throwing a match. Usually, winning more in the preliminary round only makes it easier later on.

Apparently, there is a huge incentive in badminton to throw matches. The badminton magazine Badzine conducted a study about throwing matches, since it is common knowledge that the Chinese throw matches. They found that matches were won by “walkovers” or early retirements in 20 of 99 (20%) of all-Chinese matches [link to article]. Walkovers/retirements occured in 5.3% of matches when non-Chinese athletes played their compatriots and in 0.74% of the matches between Chinese athletes and non-Chinese athletes. So the Chinese “throwing” rate is an outlier, which suggests that the Chinese badminton players are all in cahoots with each other. The Olympics scandal, however, included two Chinese teams, one Indonesian team, and one South Korea team.

Here is why the players’ strategy changed from winning all preliminary games to throwing a match:

The attempt to throw the two matches in the women’s doubles had it roots in a surprise result earlier in the day when the Chinese second seeds, Tian Qing and Zhao Yunlei, were beaten by a Danish pair. The result meant that Yang and Xiaoli had to lose to avoid meeting their compatriots before a potential showdown in the final.

A similar desire to avoid the hot favourites seemed to have cross-infected the second match, between  South Korean third seeds Ha Jung-Eun and Kim Min-Jung and Indonesian pair Meiliana Juahari and Greysia Polii [link]

And yes, the cheating was so obvious that people in the audience booed the athletes’ lack of effort:

Lori Halford, 35, who had paid £40 along with her husband for tickets to the evening session, told The Independent: “It was immediately clear that something wasn’t right. The first shot went into the net, then the next shot went into the net. The next return went under the net. There was no speed or strength to their play. There was a complete contrast to the others playing in different games who were giving it everything they could.” [link]

Throwing a badminton match is not dissimilar to sumo wrestlers throwing matches, which was discussed in detail in Freakonomics.


10 responses to “when is the optimal strategy is to throw a badminton match?

  • Thaddeus Sim

    This is why the last set of group matches at the soccer World Cup or the Euro Championships are played at the same time so as to avoid unsavory incidents like this.

  • ssssstranger

    “The Olympics scandal, however, included two Chinese teams, one Indonesian team, and one South Korea team.”
    One factual correction, the 4 pairs thrown out are 1 Chinese team, 1 Indonesian team and 2 South Korean teams. Apparently no one wants to play the world second seed pair (who happen to be also Chinese) who unexpectedly lost to Danish team and ended up in a lower bracket, in the elimination matches.

  • Dan Black

    The stats you cite suggest that Chinese players would be willing to throw matches if required. I heard an interview on the BBC with somebody involved in British badminton (sadly I can’t find it) who said that the potential of throwing matches at the end of a round robin qualification had been raised with the IBF before the tournament and they didn’t act.

    As the previous commenter suggested, playing parallel games gets round this. The World Cup introduced this after 1982 incident between West Germany and Austria. This still sometimes throw up the odd possibility for fixing results; however, it can go horribly wrong if results elsewhere change (such as Manchester City foolishly relegating themselves at the end of the 1995-96 Premier League season).

  • The Good, The Bad, & The Badminton « NotionsCapital

    [...] modern Olympic Games have seen some scandals and controversies in the past but, as Laura McLay observes, “I never thought I’d hear the words ‘badminton’ and ‘scandal’ in [...]

  • Laura McLay

    @ssssstranger: thanks for the correction.

    @Dan: The stats suggest that teams from other countries are also in cahoots with others from their own country. It’s a huge problem indeed. I had no idea. The Badzine article suggests this has been a problem for awhile, exactly what you noted. I am eagerly following all developments on this story.

  • Chris Canfield

    “The cheating was so obvious…”

    I find this to be an odd statement. Strategic sacrifices towards a larger goal have been a part of competitive sports for centuries. Chess players give up pawns to take knights. Team race drivers will send one man to run interference for the other. In Go, sacrifices happen all of the time.

    They were playing strategically, in the manner that best brought them to a gold medal, within normal performance parameters. I’m personally shocked they were thrown out for this, as it seems inherent in the rules as setup by the IOC.

  • Laura McLay

    @Chris: OK, they weren’t “cheating” so much as “throwing” the match. The NBC site had a “highlights” reel of one of the matches. It’s hard to say how bad it was for the audience, since I didn’t see a video of the entire match. From what I saw, many of the plays looked like a good high school match. For a minute, I thought 18-year-old-me had a chance against an Olympian!

    You bring up a good point. Tour de France cycling is a little disturbing, because all team members except one are “sacrificed” for the greater good. Here, I think, “gaming the strategy” is viewed differently because they are “playing” the officials not their opponents, whereas the other instances you mention like chess ultimately are trying to win each match. Winning by technicalities is generally not tolerated well by fans (except in basketball, where purposely fouling at the end of the game is just, well, part of the game). The officials do need to come up with a better tournament design to avoid the “winning by technicality” incentives.

    I did hear another good defense: NFL & NBA teams purposely lose games to get better draft picks. Maybe I’ll change my mind about this…

  • Jay Simon

    Most top-level badminton tournaments are not set up this way, primarily because people recognize that such a situation could arise. I have no idea why it was decided to change the structure for the Olympics this year, but I have a very hard time blaming the players for trying to lose individual matches in an effort to increase their probabilities of winning a medal.

    Regarding Chinese players throwing matches, it’s often for a different reason. When their top players/teams have already done well enough in tournaments to qualify for the Olympics, world championships, etc., they will often throw matches against other Chinese players to help THOSE players qualify for the prestigious events. As a badminton player and fan, I consider that to be “cheating” much more than I would what the 4 women’s doubles teams did this week.

  • Dan Black

    Bringing this back to an OR perspective I think this touches on issues regarding the difference between theory and reality. I think anybody who has developed models for real world situations will have experienced presenting results/ideas only for them to be knocked back as impractical. This is a natural part of the model development process.

    I think in this case the theory says throw the match. This decision was achieved using the assumption that there would be no recourse to doing so. The IBF may have been reacting to public opinion by penalising the players but I have also seen it said in the media that there is a rule that you have to try and win every match you play. Was this taken into account when the players/coaches made their decisions?

    Maybe there was also an issue with how the decision was implemented. The players were so obviously throwing the match that it prompted a response.

  • Laura McLay

    @Jay and @Dan: Excellent points! Perhaps the officials should have created a list of what constitutes cheating. I know I do so when I give take home exames. It’s always surprising when students are surprised to learn that I consider anything to be cheating other than talking to their classmates about their understanding of what the question is asking. And I have had few problems with cheating.

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