HEMA Myth: Double Outs Increase the Rate of Doubles

Dealing with both competitors simultaneously striking each other is the bane of fencing tournament design in any discipline. In HEMA there are a number of different approaches to deal with the issue, one of which is the Double Hit. The double hit assigns no judgement as to who was or was not at fault, and simply identifies that both fighters struck each other “simultaneously”. A common accompaniment to the Double Hit is the Double Out, where after a certain number of double hits in a match both fighters will be considered to have lost.

The exact rationale for this is a little out of scope for now. It’s a complicated question with a lot of moving parts. But suffice to say something as harsh as a double loss for both fighters has people with firm opinions on the practice. Some argue in favor of the double out, in that it is a way to introduce negative-sum elements into the match and without such a penalty there is no reason not to double. Others argue that it is a poor design practice in that a single fencer can, through their choices, force a negative outcome on both parties.

This article isn’t to hash through these arguments. Why I am writing this is because there seems to be a new trend among opponents of the Double Out rule, to claim that the practice of tournament double outs causes people to worry about doubling so much that they double more. And removing Double Outs actually leads to fewer doubles.

If I needed a textbook example of motivated reasoning, this would probably be the one. But slinging back and forth claims of a more logical argument is not science, in fact it is about as anti-science as you can get. Science likes data. And I have data. Data I will use to call bullshit on this made up “fact”.

Tremble in fear, users of bad HEMA stats. For now I am posting on my blog.

Data

So what data is available? Obviously we don’t have controlled experiments to study, so the best we can do is look at existing tournament records. All tournaments work a little differently, so they don’t necessarily have an explicit “Double Hit” as a scoring action. I did a search for longsword tournaments which had at least 1 “Double Hit” indicated in the HEMA Scorecard database, and was able to come up with a list of 71 events, and a total of 42,026 exchanges (not all the tournaments used afterblows, so all analysis is on “double” and “clean” flagged exchanges).

Wow! Not only does the claim of “removing double outs lowers double hits” fall flat on its head, we see a very clear trend in the opposite direction. Though this plot still begs two questions:

  1. What do you mean that the “without Double Outs” column is underestimated?
  2. Why did you put stuff like that disclaimer and the logo in the chart?

I’ll answer #2 first: because people keep asking me if there is something that they can share when people make this claim. Hopefully someone will find having a self-contained plot helpful. To answer question #1 we have to think a little bit about how to get this data in the first place. (The rest of the article will be about data mining techniques, so you can leave now if you just wanted to hear me get worked up about people making up stats.)

Data Parsing

It is very easy to calculate the double hit percentage:

It has color, so it can’t be a scary formula. (Now that I’m done being salty I can go back to my usual “try to be funny.”)

The hard part is determining if a tournament does, or does not, have a double out rule. If you see a match ended on a double out, then you can be pretty certain. If you see that no matches doubled out, you don’t know for sure. It could be that there were no double outs, or it could be that people were doubling so infrequently that a match never got to the double out point.

So if you take all the tournaments which allowed double outs, but had a very low number of doubles, and roll it into the stats of the no double outs tournaments it will drive the double hit rate of the no double out tournaments down. Which is the under-estimation of which I mentioned in my article. 

I already had to do some data pruning with the knowledge I had available. Over and above what the data returned I:

  • Deleted tournaments with weird rules.
  • Reclassified tournaments I knew had double out rules, but didn’t record a single double out.

This leaves, I’m sure, a lot of tournaments with double out rule still counted in the no double outs column. But the purpose of this investigation was not to determine the exact ratio for each, it was to see if the claim had any validity. And it is exceedingly obvious it does not, even with a bunch of extra data stacked in its favor.

Conclusion

There are plenty of valid reasons why you can not like double outs from a game design point of view. Elaborate on these points and work towards whatever your vision is. Just don’t make stuff up and parade it around like a fact that supports your position.

Stats for Nerds

Here are the events which I took data for. This is based on longswords only.

Double Out Tournaments

Event clean afterblow double numDoubleOuts double Hit %
Combat Con 2016 763 64 87 2 10.24%
Combat Con 2015 583 81 71 2 10.86%
Rose City Classic 2016 430 45 46 1 9.66%
SoCal Swordfight 2015 773 87 96 4 11.05%
SoCal Swordfight 2017 739 99 91 1 10.96%
Combat Con 2017 815 108 95 2 10.44%
PNW HEMA Gathering 2014 430 59 48 1 10.04%
Rose City Classic 2017 395 68 47 1 10.63%
SoCal Swordfight 2018 819 103 99 4 10.78%
Ragnarök 2018 150 0 13 1 7.98%
All’s Faire HEMA Tournament 2018 154 24 16 1 9.41%
Combat Con 2018 936 148 95 4 9.21%
Combat Con 2019 731 142 74 6 9.19%
Nordschlag 2018 122 14 31 1 20.26%
Fight Night 2018 43 0 5 1 10.42%
SoCal Swordfight 2019 1166 168 154 7 11.67%
Queen’s Gambit 2019 169 43 17 4 9.14%
Baton Rouge Open 2019 1283 220 130 4 9.20%
New Amsterdam HEMA Open 2019 635 45 76 2 10.69%
Polyclash 2019 375 122 69 2 15.54%
SERFO 2019 280 7 50 2 15.15%
SoCal Swordfight 2020 1413 254 149 8 9.54%
Cornhusker State Games 2020 413 59 35 4 7.81%
Green Chapel Tourney 2021 247 62 27 4 9.85%
Donnybrook 2021 670 114 84 4 11.14%
Combat Con 2021 1082 305 88 8 7.52%
Pennsylvania HEMA Open 2021 1070 174 158 12 12.87%
Longpoint 2019 673 152 58 0 7.93%
PNW HEMA Gathering 2015 469 61 43 0 8.40%
Victoria Highland Games Open 2018 521 64 38 0 6.80%
Ars Gladii 20th Anniversary Invitational 2019 197 25 19 0 8.80%
Eurofest 2017 184 21 14 0 7.07%
Victoria Highland Games 2019 667 88 62 0 8.50%
Nordschlag 2019 123 0 2 0 1.60%

Non Double Out Tournaments

Event clean afterblow double numDoubleOuts double Hit %
Dune Longsword Competition 2016 218 0 18 0 7.63%
Sandstorm 2017 215 34 21 0 8.90%
Cornhusker State Games 2018 244 61 18 0 6.87%
The Battle of Buffalo 2018 216 52 32 0 12.90%
1º Torneio de Esgrima Histórica de Valinhos 2018 69 35 16 0 18.82%
Long Island Point 2018 317 0 45 0 12.43%
Polish Championships 2018 742 0 269 0 26.61%
Polyclash 2018 213 83 34 0 13.77%
Showdown in No-Town 2019 197 20 65 0 24.81%
Exeter Longsword Competition 2019 470 181 38 0 7.48%
Durchschlag 2019 531 0 298 0 35.95%
Symphony of Steel 2019 344 100 76 0 18.10%
Clash of Claymores 2019 1363 52 165 0 10.80%
IFG Spring Fling 2019 448 0 27 0 5.68%
Flügelschlag Stuttgart 2019 346 0 117 0 25.27%
Black Horns Cup 2019 556 0 339 0 37.88%
Torneo Acero de Aconcagua 2019 433 49 48 0 9.98%
Cornhusker State Games 2019 218 67 15 0 6.44%
Fairfax Mini Ren Faire 2019 122 0 13 0 9.63%
Flower of Battle 2019 642 192 8 0 1.23%
Albion Cup 2019 898 332 31 0 3.34%
Hojas de Plata 2019 391 50 38 0 8.86%
Gesellen Fechten 2019 1108 0 318 0 22.30%
Wessex League – Exeter 2019 661 114 20 0 2.94%
Wasatch HEMA Fall Tournament 2019 302 51 8 0 2.58%
IV Mistrzostwa Polski 2019 743 0 353 0 32.21%
Turniej Fechtunku Historycznego HFC 2019 314 0 107 0 25.42%
Ciudad de los Reyes 2019 104 73 20 0 16.13%
Durchschlag 2020 637 0 444 0 41.07%
The Plough Tournament 2nd 2020 414 100 7 0 1.66%
Autumn Fechten 2020 381 0 125 0 24.70%
Spring Fechten 2021 590 0 166 0 21.96%
Cornhusker State Games 2021 560 111 30 0 5.08%
Unicorn Fight Club 2021 115 43 25 0 17.86%
Wasatch HEMA Local 2021 274 45 21 0 7.12%
Black Horns Cup 2021 460 0 290 0 38.67%
Bellum Vitudurum 2021 565 0 233 0 29.20%
About Sean Franklin 96 Articles
Sean has a Bachelor's Degree in Mechatronic Systems Engineering, and is currently employed as a Controls Engineer. He is passionate about developing more analytical ways to view sword fighting, wishing to develop evidence based standards for protective gear and rule sets informed by tournament statistics. His martial arts history includes competitive success, medaling in international competitions for Longsword, Messer, Grappling, Rapier, and Cutting. In addition to competition Sean has been invited to instruct at a number of events across North America and Europe.