Posts filed under Sports statistics (179)

July 28, 2014

The Games: How we’re doing

Statistics New Zealand is running the numbers during the Glasgow 2014 Commonwealth Games to show how many medals countries are winning relative to their population.  At the time of posting, we were third on a per-million-of-population basis. Check it out here.

July 27, 2014

More rugby stats

From Offsetting Behaviour (specifically, Seamus Hogan): How unfair is the Super 15 schedule?

The was prompted by one of the posts on the (apparently new) blog Sport Loves Data, by Kirdan Lees.

July 23, 2014

NRL Predictions for Round 20

Team Ratings for Round 20

The basic method is described on my Department home page. I have made some changes to the methodology this year, including shrinking the ratings between seasons.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Current Rating Rating at Season Start Difference
Sea Eagles 8.06 9.10 -1.00
Roosters 8.02 12.35 -4.30
Rabbitohs 6.67 5.82 0.90
Warriors 5.50 -0.72 6.20
Cowboys 4.07 6.01 -1.90
Broncos 3.33 -4.69 8.00
Panthers 1.50 -2.48 4.00
Storm 0.42 7.64 -7.20
Bulldogs 0.06 2.46 -2.40
Knights -2.24 5.23 -7.50
Titans -3.51 1.45 -5.00
Dragons -4.19 -7.57 3.40
Wests Tigers -5.06 -11.26 6.20
Raiders -5.42 -8.99 3.60
Sharks -8.78 2.32 -11.10
Eels -10.21 -18.45 8.20

 

Performance So Far

So far there have been 136 matches played, 78 of which were correctly predicted, a success rate of 57.4%.

Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Sharks vs. Cowboys Jul 18 18 – 36 -6.10 TRUE
2 Eels vs. Rabbitohs Jul 18 12 – 32 -10.60 TRUE
3 Roosters vs. Panthers Jul 19 32 – 12 8.90 TRUE
4 Storm vs. Raiders Jul 19 28 – 14 9.40 TRUE
5 Broncos vs. Warriors Jul 19 28 – 22 1.40 TRUE
6 Knights vs. Titans Jul 20 8 – 22 10.00 FALSE
7 Wests Tigers vs. Bulldogs Jul 20 46 – 18 -6.40 FALSE
8 Dragons vs. Sea Eagles Jul 21 12 – 21 -7.40 TRUE

 

Predictions for Round 20

Here are the predictions for Round 20. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Game Date Winner Prediction
1 Knights vs. Roosters Jul 25 Roosters -5.80
2 Broncos vs. Storm Jul 25 Broncos 7.40
3 Panthers vs. Sharks Jul 26 Panthers 14.80
4 Titans vs. Eels Jul 26 Titans 11.20
5 Bulldogs vs. Cowboys Jul 26 Bulldogs 0.50
6 Warriors vs. Sea Eagles Jul 27 Warriors 1.90
7 Wests Tigers vs. Dragons Jul 27 Wests Tigers 3.60
8 Raiders vs. Rabbitohs Jul 28 Rabbitohs -7.60

 

Super 15 Predictions for the Semi-finals

Team Ratings for the Semi-finals

The basic method is described on my Department home page. I have made some changes to the methodology this year, including shrinking the ratings between seasons.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Current Rating Rating at Season Start Difference
Waratahs 9.66 1.67 8.00
Crusaders 8.78 8.80 -0.00
Sharks 5.34 4.57 0.80
Hurricanes 2.89 -1.44 4.30
Bulls 2.88 4.87 -2.00
Brumbies 2.76 4.12 -1.40
Chiefs 2.23 4.38 -2.10
Stormers 1.68 4.38 -2.70
Blues 1.44 -1.92 3.40
Highlanders -2.54 -4.48 1.90
Lions -3.39 -6.93 3.50
Force -4.67 -5.37 0.70
Reds -4.98 0.58 -5.60
Cheetahs -5.55 0.12 -5.70
Rebels -9.53 -6.36 -3.20

 

Performance So Far

So far there have been 122 matches played, 80 of which were correctly predicted, a success rate of 65.6%.

Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Brumbies vs. Chiefs Jul 19 32 – 30 5.00 TRUE
2 Sharks vs. Highlanders Jul 19 31 – 27 13.00 TRUE

 

Predictions for the Semi-finals

Here are the predictions for the Semi-finals. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Game Date Winner Prediction
1 Crusaders vs. Sharks Jul 26 Crusaders 7.40
2 Waratahs vs. Brumbies Jul 26 Waratahs 9.40

 

July 17, 2014

NRL Predictions for Round 19

Team Ratings for Round 19

The basic method is described on my Department home page. I have made some changes to the methodology this year, including shrinking the ratings between seasons.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Current Rating Rating at Season Start Difference
Sea Eagles 7.87 9.10 -1.20
Roosters 6.97 12.35 -5.40
Warriors 5.98 -0.72 6.70
Rabbitohs 5.76 5.82 -0.10
Cowboys 2.96 6.01 -3.10
Bulldogs 2.96 2.46 0.50
Broncos 2.85 -4.69 7.50
Panthers 2.54 -2.48 5.00
Storm -0.05 7.64 -7.70
Knights -0.14 5.23 -5.40
Dragons -4.01 -7.57 3.60
Raiders -4.94 -8.99 4.10
Titans -5.61 1.45 -7.10
Sharks -7.67 2.32 -10.00
Wests Tigers -7.96 -11.26 3.30
Eels -9.30 -18.45 9.20

 

Performance So Far

So far there have been 128 matches played, 72 of which were correctly predicted, a success rate of 56.2%.

Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Sea Eagles vs. Wests Tigers Jul 11 40 – 8 17.70 TRUE
2 Warriors vs. Eels Jul 12 48 – 0 14.10 TRUE
3 Storm vs. Bulldogs Jul 12 4 – 6 2.40 FALSE
4 Titans vs. Raiders Jul 13 20 – 36 8.00 FALSE
5 Sharks vs. Knights Jul 13 18 – 31 -0.70 TRUE
6 Panthers vs. Broncos Jul 14 35 – 34 5.00 TRUE

 

Predictions for Round 19

Here are the predictions for Round 19. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Game Date Winner Prediction
1 Sharks vs. Cowboys Jul 18 Cowboys -6.10
2 Eels vs. Rabbitohs Jul 18 Rabbitohs -10.60
3 Roosters vs. Panthers Jul 19 Roosters 8.90
4 Storm vs. Raiders Jul 19 Storm 9.40
5 Broncos vs. Warriors Jul 19 Broncos 1.40
6 Knights vs. Titans Jul 20 Knights 10.00
7 Wests Tigers vs. Bulldogs Jul 20 Bulldogs -6.40
8 Dragons vs. Sea Eagles Jul 21 Sea Eagles -7.40

 

Super 15 Predictions for the Qualifying Finals

Team Ratings for the Qualifying Finals

The basic method is described on my Department home page. I have made some changes to the methodology this year, including shrinking the ratings between seasons.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Current Rating Rating at Season Start Difference
Waratahs 9.66 1.67 8.00
Crusaders 8.78 8.80 -0.00
Sharks 5.92 4.57 1.40
Brumbies 2.97 4.12 -1.10
Hurricanes 2.89 -1.44 4.30
Bulls 2.88 4.87 -2.00
Chiefs 2.02 4.38 -2.40
Stormers 1.68 4.38 -2.70
Blues 1.44 -1.92 3.40
Highlanders -3.12 -4.48 1.40
Lions -3.39 -6.93 3.50
Force -4.67 -5.37 0.70
Reds -4.98 0.58 -5.60
Cheetahs -5.55 0.12 -5.70
Rebels -9.53 -6.36 -3.20

 

Performance So Far

So far there have been 120 matches played, 78 of which were correctly predicted, a success rate of 65%.

Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Blues vs. Chiefs Jul 11 8 – 11 2.70 FALSE
2 Brumbies vs. Force Jul 11 47 – 25 8.50 TRUE
3 Bulls vs. Rebels Jul 11 40 – 7 14.20 TRUE
4 Crusaders vs. Highlanders Jul 12 34 – 8 12.80 TRUE
5 Reds vs. Waratahs Jul 12 3 – 34 -9.60 TRUE
6 Lions vs. Cheetahs Jul 12 60 – 25 0.80 TRUE
7 Stormers vs. Sharks Jul 12 10 – 29 0.60 FALSE

 

Predictions for the Qualifying Finals

Here are the predictions for the Qualifying Finals. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Game Date Winner Prediction
1 Brumbies vs. Chiefs Jul 19 Brumbies 5.00
2 Sharks vs. Highlanders Jul 19 Sharks 13.00

 

July 9, 2014

NRL Predictions for Round 18

Team Ratings for Round 18

The basic method is described on my Department home page. I have made some changes to the methodology this year, including shrinking the ratings between seasons.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Current Rating Rating at Season Start Difference
Roosters 6.97 12.35 -5.40
Sea Eagles 6.56 9.10 -2.50
Rabbitohs 5.76 5.82 -0.10
Warriors 3.11 -0.72 3.80
Cowboys 2.96 6.01 -3.10
Panthers 2.96 -2.48 5.40
Bulldogs 2.50 2.46 0.00
Broncos 2.43 -4.69 7.10
Storm 0.40 7.64 -7.20
Knights -1.29 5.23 -6.50
Titans -3.51 1.45 -5.00
Dragons -4.01 -7.57 3.60
Eels -6.44 -18.45 12.00
Sharks -6.52 2.32 -8.80
Wests Tigers -6.64 -11.26 4.60
Raiders -7.04 -8.99 2.00

 

Performance So Far

So far there have been 122 matches played, 68 of which were correctly predicted, a success rate of 55.7%.

Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Bulldogs vs. Sea Eagles Jul 04 23 – 16 -1.10 FALSE
2 Dragons vs. Cowboys Jul 05 27 – 24 -3.80 FALSE
3 Roosters vs. Sharks Jul 05 28 – 30 22.20 FALSE
4 Wests Tigers vs. Panthers Jul 06 10 – 26 -2.60 TRUE
5 Rabbitohs vs. Titans Jul 07 10 – 14 17.60 FALSE

 

Predictions for Round 18

Here are the predictions for Round 18. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Game Date Winner Prediction
1 Sea Eagles vs. Wests Tigers Jul 11 Sea Eagles 17.70
2 Warriors vs. Eels Jul 12 Warriors 14.10
3 Storm vs. Bulldogs Jul 12 Storm 2.40
4 Titans vs. Raiders Jul 13 Titans 8.00
5 Sharks vs. Knights Jul 13 Knights -0.70
6 Panthers vs. Broncos Jul 14 Panthers 5.00

 

Super 15 Predictions for Round 19

Team Ratings for Round 19

The basic method is described on my Department home page. I have made some changes to the methodology this year, including shrinking the ratings between seasons.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Current Rating Rating at Season Start Difference
Waratahs 8.40 1.67 6.70
Crusaders 7.96 8.80 -0.80
Sharks 4.75 4.57 0.20
Hurricanes 2.89 -1.44 4.30
Stormers 2.85 4.38 -1.50
Brumbies 2.13 4.12 -2.00
Blues 1.82 -1.92 3.70
Bulls 1.76 4.87 -3.10
Chiefs 1.63 4.38 -2.70
Highlanders -2.30 -4.48 2.20
Cheetahs -3.62 0.12 -3.70
Reds -3.72 0.58 -4.30
Force -3.84 -5.37 1.50
Lions -5.31 -6.93 1.60
Rebels -8.41 -6.36 -2.10

 

Performance So Far

So far there have been 113 matches played, 73 of which were correctly predicted, a success rate of 64.6%.

Here are the predictions for last week’s games.


Game Date Score Prediction Correct
1 Chiefs vs. Hurricanes Jul 04 24 – 16 0.20 TRUE
2 Lions vs. Rebels Jul 04 34 – 17 5.70 TRUE
3 Crusaders vs. Blues Jul 05 21 – 13 8.80 TRUE
4 Force vs. Reds Jul 05 30 – 20 1.30 TRUE
5 Stormers vs. Bulls Jul 05 16 – 0 1.90 TRUE
6 Cheetahs vs. Sharks Jul 05 27 – 20 -7.70 FALSE
7 Waratahs vs. Highlanders Jul 06 44 – 16 12.90 TRUE

 

Predictions for Round 19

Here are the predictions for Round 19. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Game Date Winner Prediction
1 Blues vs. Chiefs Jul 11 Blues 2.70
2 Brumbies vs. Force Jul 11 Brumbies 8.50
3 Bulls vs. Rebels Jul 11 Bulls 14.20
4 Crusaders vs. Highlanders Jul 12 Crusaders 12.80
5 Reds vs. Waratahs Jul 12 Waratahs -9.60
6 Lions vs. Cheetahs Jul 12 Lions 0.80
7 Stormers vs. Sharks Jul 12 Stormers 0.60

 

July 5, 2014

Once is accident, twice is coincidence

Back in 2010, a piece in Slate pointed out that a country’s success in the 2010 and 2006 World Cup knock-out rounds was strongly correlated with the proportion of the population infected by Toxoplasma gondii.  In 2010, Toxoplasma seroprevalence predicted all eight knockout-round wins; in 2006 it predicted seven of eight.

Toxoplasma, in case you weren’t introduced when you met it, is a single-celled organism that can live, and reproduce asexually, in pretty much any warm-blooded animal, but can only reproduce sexually in the guts of cats. That’s not the interesting part. The interesting part is that in rodents the parasite has effects on the brain, making the animal less cautious and more likely to end up in the gut of a cat. There’s some evidence Toxoplasma also has effects on human behaviour, though that’s still controversial.

Now, in 2014, I see a Tweet from Australian biologist Michael Whitehead

So, three times is enemy action?

There are good reasons to be sceptical: the football rankings haven’t changed all that much since 2006, so this isn’t really three independent tests. Also, the seroprevalence data is for the countries as a whole, not for the team members.  Still, in contrast to the predictions using Octopus vulgaris in the last World Cup, it’s not completely out of the question that there could be a real effect.

June 25, 2014

NRL Predictions for Round 16

Team Ratings for Round 16

The basic method is described on my Department home page. I have made some changes to the methodology this year, including shrinking the ratings between seasons.

Here are the team ratings prior to this week’s games, along with the ratings at the start of the season.

Current Rating Rating at Season Start Difference
Roosters 9.74 12.35 -2.60
Rabbitohs 7.89 5.82 2.10
Sea Eagles 6.70 9.10 -2.40
Broncos 4.31 -4.69 9.00
Cowboys 3.41 6.01 -2.60
Warriors 2.59 -0.72 3.30
Panthers 2.25 -2.48 4.70
Storm 1.81 7.64 -5.80
Bulldogs 1.71 2.46 -0.80
Knights -1.95 5.23 -7.20
Wests Tigers -4.77 -11.26 6.50
Titans -5.41 1.45 -6.90
Eels -5.78 -18.45 12.70
Dragons -6.09 -7.57 1.50
Raiders -7.68 -8.99 1.30
Sharks -10.52 2.32 -12.80

 

Performance So Far

So far there have been 110 matches played, 63 of which were correctly predicted, a success rate of 57.3%.

Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Raiders vs. Bulldogs Jun 20 14 – 22 -4.10 TRUE
2 Warriors vs. Broncos Jun 21 19 – 10 1.30 TRUE
3 Sharks vs. Sea Eagles Jun 21 0 – 26 -9.80 TRUE
4 Storm vs. Eels Jun 22 46 – 20 9.00 TRUE
5 Titans vs. Dragons Jun 22 18 – 19 6.70 FALSE
6 Knights vs. Cowboys Jun 23 36 – 28 -2.90 FALSE

 

Predictions for Round 16

Here are the predictions for Round 16. The prediction is my estimated expected points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.

Game Date Winner Prediction
1 Sea Eagles vs. Roosters Jun 27 Sea Eagles 1.50
2 Broncos vs. Sharks Jun 27 Broncos 19.30
3 Wests Tigers vs. Raiders Jun 28 Wests Tigers 7.40
4 Cowboys vs. Rabbitohs Jun 28 Cowboys 0.00
5 Warriors vs. Panthers Jun 29 Warriors 4.80
6 Eels vs. Knights Jun 29 Eels 0.70
7 Dragons vs. Storm Jun 30 Storm -3.40