7: Shuster’s chance of gold


If this blog has two specialties they are analyzing first shots against Rachel Homan (thanks to the shot play-by-play at curlingzone.com, I have updated last week’s post with more extensive data) and Monte Carlo simulations of various events.

To get people in the mood for that kind of thing, it’s only natural to look at some famous results from the past. First up is the seemingly improbable gold medal won by the USA in Pyeongchang.

This exercise involves taking the predicted win probability based on the ratings before an event (hey, we have a ratings archive now) and run the event on our laptop one million times. From there, we get a probability for each team to win the event based on its performance to that point.

Heading into the 2018 Olympics, John Shuster’s team was ranked 18th in my system. Not exactly the type of team you’d expect to break an American gold-medal drought in curling. However, the situation wasn’t as bleak as that ranking suggests. There were 13 Canadian teams ranked ahead of Shuster and this being the Olympics, only one of them could compete in the event. For that reason, the field for the Olympics is quite a bit weaker than a Grand Slam event or even the Brier.

And given that the field is just ten teams, merely making it to the Olympics gives you a chance. Four teams make the medal round, and there were only three top-15 teams in the field, so it wouldn’t have been crazy to predict Shuster to make the medal round. And there was no page playoff, so his team just needed to sneak into the medal round and win twice to earn the gold. You could kind of see how it would be possible.

OK, not really. But if you were rooting for the Americans, it was conceivable things could get at least get interesting. Well, here is what my computer would have said.

rank     last_name rating pool playoff title finish
   2      Edin SWE 12.393    A    84.0% 36.9%     2
   4       Koe CAN 12.208    A    77.4  27.7      4 
   6   De Cruz SUI 11.922    A    64.8  16.5      3
  16    Ulsrud NOR 11.379    A    37.0   4.8
  18   Shuster USA 11.361    A    36.1   4.6      1
  19     Smith GBR 11.312    A    33.8   4.0
  21       Kim KOR 11.248    A    30.7   3.4
  39   Stjerne DEN 10.805    A    14.0   0.8
  40  Morozumi JPN 10.799    A    13.8   0.8
  53  Retornaz ITA 10.579    A     8.4   0.4

Compare this to the pre-event odds according to Westgate courtesy of gamingtoday.com:

Switzerland was disrespected relative to my ratings with the odds painting a picture of Canada and Sweden being the clear favorites and Canada given a distinct edge among the two. That appears to be a little bonkers but was probably influenced by the Canadians having won the last three golds in the men’s event. Switzerland would take bronze, beating Canada in the third-place game and freezing them out of any medal at all, so chalk one up for the DT ratings I guess.

Shuster had a 1-in-22 chance per my probabilities, fifth-best in the field. How that relates to the original Miracle on Ice is hard to say. (I am not aware of an international hockey model especially one that goes back to 1980.) But we can use this method on any curling event if the past or future for which we have ratings.

There is another American victory worth looking at that occurred about two months after the Olympics. The 2018 Players’ Championship was won by Jamie Sinclair’s team, the first Grand Slam won by an American squad. (Thanks to Sinclair’s third, Alex Agre, for requesting this analysis.) Sinclair was ranked 15th in the world which was the 11th-best team in this 12-team field.

So you might guess that winning this event would be more improbable, however the format offsets that idea a bit. Eight of the 12 teams made the playoff round, which creates the interesting mathematical riddle where 11 of the 12 teams had more than a 50% of getting to the playoffs.

But the larger 12-team field and its increased depth compare to men’s curling at the Olympics are the most important factors. In the end, Sinclair had a 2.7% chance of winning the event, making it more improbable than Shuster’s gold.

rank  last_name rating pool playoff title finish
   1      Jones 12.602    A    85.3% 24.5%   2
   2      Homan 12.451    A    81.3  19.0
   3 Hasselborg 12.320    B    84.4  16.5   QF
   4      Carey 11.992    B    75.7   8.8
   6   Einarson 11.796    B    69.8   5.9   SF
   7  Tirinzoni 11.784    B    69.4   5.7   SF
  10        Kim 11.748    A    59.2   4.5
  11   Muirhead 11.738    A    58.7   4.4   QF
  12       Roth 11.664    A    56.2   3.7   QF
  13     Rocque 11.578    A    53.0   3.0   
  15   Sinclair 11.471    B    58.7   2.7    1
  26   Fujisawa 11.200    B    48.3   1.3   QF

By the way, pool play was crazy as Homan and Carey, the second- and fourth-ranked teams in the world, respectively, combined to go 1-9. They combined for one or zero wins in just 1,287 (0.13%) of the million simulations.

Now let’s apply our powers to the future! Curling makes its return this week as the Schweizer Cup gets underway in Basel. (Technically, the return of curling was the New Zealand Nationals three weeks ago, but none of the participants had ratings here.) This event is limited to Swiss teams but the good news is that there will be a YouTube stream, possibly even with German-language commentary. Fingers crossed it’s not geo-blocked. Action begins on Thursday at 1500 CET, which means curling for breakfast if you’re in North America.

The men’s event does not include Peter De Cruz’s eighth-ranked team, so the Schweizer Cup becomes the Schwaller Cup as Yannick Schwaller is the headliner of this event. The men’s side has ten teams in two pools and the top two teams in each pool make the playoff round.

rank rating   last_name pool playoff title
22 11.474 Schwaller A 98.0% 67.0%
61 10.398 Hess B 91.3 18.4
134 9.585 Schnider B 63.9 5.4
132 9.592 Hösli A 48.3 4.6
153 9.352 Klossner A 33.6 2.4
NA 8.907 R Iseli B 23.6 0.8
181 8.982 Heinimann A 17.5 0.8
NA 8.599 Bangerter B 13.1 0.3
192 8.382 J Iseli B 8.2 0.1
NA 8.147 Hürlimann A 2.6 0.04

The women’s side features a seven-team round robin followed by a title game between the top two. That seems pretty likely to involve Tirinzoni and Stern, the two top-20 teams in the field. Irene Schori has the 41st-ranked team in the world and is the only realistic spoiler. Binia Feltscher’s 36th-ranked team that has occasionally appeared in Grand Slams over the years no longer exists. Feltscher has moved on to coaching the country’s top junior team, skipped by Selina Witschonke.

rank rating   last_name pool playoff title
   5 12.525   Tirinzoni    A    93.6% 65.6%   
  14 11.888       Stern    A    77.2  29.1
  41 10.999      Schori    A    19.8   4.2
  64 10.400  Witschonke    A     5.1   0.7
  76 10.270       Wüest    A     3.6   0.4
 124  9.589     Mueller    A     0.5   0.03
 132  9.450 Schwizgebel    A     0.3   0.02

User comments
  1. Dianna · 2020.08.19 · 11:49 am

    With that in mind, was the Korean Women’s silver in 2018 more or less unlikely than Shuster’s Gold?

    1. kenpom · 2020.08.19 · 5:28 pm

      Actually, Korea winning silver wasn’t that big of an upset. At least, it shouldn’t have been since they were 4th in the field based on my ratings pre-Olympics. But I see that they were given 50-1 odds?!? I get the feeling Olympic odds are set based on a country’s history in the Olympics, and since Korea had never appeared before, it was just assumed they weren’t very good. 🙁

  2. John · 2020.08.19 · 5:10 pm


    Looks like streaming coverage doesn’t start until the Friday draws.

    1. kenpom · 2020.08.19 · 5:17 pm

      Ah, bummer. Thanks for the info.

  3. Curling Robots · 2020.08.20 · 2:30 pm

    Fascinating! It’s funny, we remember back in 2018 thinking everything happening at the Players’ was very surprising, but to see how statistically unlikely it actually was (!)

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