July 28, 2020

Super Rugby Aotearoa Predictions for Round 8

Team Ratings for Round 8

The basic method is described on my Department home page.
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
Crusaders 14.68 15.15 -0.50
Hurricanes 7.98 8.31 -0.30
Blues 6.88 5.39 1.50
Chiefs 5.41 7.94 -2.50
Highlanders 1.61 -0.22 1.80

 

Performance So Far

So far there have been 14 matches played, 9 of which were correctly predicted, a success rate of 64.3%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Crusaders vs. Hurricanes Jul 25 32 – 34 13.30 FALSE
2 Blues vs. Chiefs Jul 26 21 – 17 6.40 TRUE

 

Predictions for Round 8

Here are the predictions for Round 8. 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 Chiefs vs. Crusaders Aug 01 Crusaders -4.80
2 Highlanders vs. Blues Aug 02 Blues -0.80

 

NRL Predictions for Round 12

Team Ratings for Round 12

The basic method is described on my Department home page.
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
Storm 14.03 12.73 1.30
Roosters 12.40 12.25 0.20
Raiders 6.55 7.06 -0.50
Eels 5.47 2.80 2.70
Panthers 3.61 -0.13 3.70
Rabbitohs 2.55 2.85 -0.30
Sharks 1.94 1.81 0.10
Wests Tigers 0.96 -0.18 1.10
Sea Eagles 0.62 1.05 -0.40
Knights -2.26 -5.92 3.70
Dragons -4.00 -6.14 2.10
Bulldogs -5.93 -2.52 -3.40
Cowboys -6.32 -3.95 -2.40
Warriors -7.34 -5.17 -2.20
Broncos -10.48 -5.53 -4.90
Titans -13.79 -12.99 -0.80

 

Performance So Far

So far there have been 88 matches played, 57 of which were correctly predicted, a success rate of 64.8%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Eels vs. Wests Tigers Jul 23 26 – 16 5.90 TRUE
2 Cowboys vs. Sea Eagles Jul 24 12 – 24 -4.00 TRUE
3 Broncos vs. Storm Jul 24 8 – 46 -20.80 TRUE
4 Roosters vs. Warriors Jul 25 18 – 10 26.00 TRUE
5 Sharks vs. Dragons Jul 25 28 – 24 6.30 TRUE
6 Raiders vs. Rabbitohs Jul 25 18 – 12 6.00 TRUE
7 Knights vs. Bulldogs Jul 26 12 – 18 7.00 FALSE
8 Titans vs. Panthers Jul 26 14 – 22 -16.40 TRUE

 

Predictions for Round 12

Here are the predictions for Round 12. 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 Dragons vs. Rabbitohs Jul 30 Rabbitohs -4.50
2 Wests Tigers vs. Warriors Jul 31 Wests Tigers 12.80
3 Broncos vs. Sharks Jul 31 Sharks -10.40
4 Roosters vs. Titans Aug 01 Roosters 28.20
5 Cowboys vs. Raiders Aug 01 Raiders -10.90
6 Sea Eagles vs. Panthers Aug 01 Panthers -1.00
7 Bulldogs vs. Eels Aug 02 Eels -9.40
8 Storm vs. Knights Aug 02 Storm 16.30

 

July 27, 2020

Rogue polls

I wrote about ordinary sampling variation and ‘rogue polls’ for The Spinoff

 

July 24, 2020

Hard, soft, and real

In clinical trials we make two important distinctions between measurements. There are ‘hard’ and ‘soft’ outcomes — ‘hard’ ones are objectively and reproducibly measurable, ‘soft’ ones have some subjectivity and observer bias.  There are also ‘surrogate’ and ‘real’ or ‘patient-centered’ outcomes. ‘Real’ outcomes are what we care about; ‘surrogate’ outcomes are things we measure because we can measure them well and we expect them to correlate with real outcomes. Hard and soft outcomes are valuable; real and surrogate outcomes are valuable; you don’t want to confuse them.

There’s a story on NewsHub headlined Bisexual men are real, study finds. One of the researchers had previously doubted this, but has now been convinced, and has paper in PNAS about an analysis combining data from many previous studies.  These studies involve wiring someone’s penis up to detect arousal and then showing him erotic images.  The claim is that these measurements are objective

If men who self-report Kinsey scores in the bisexual range indeed have relatively bisexual arousal patterns, then both Minimum Arousal and the Bisexual Arousal Composite should show an inverted U-shaped distribution across the Kinsey range (i.e., men who self-identify as 0 [exclusively heterosexual] and 6 [exclusively homosexual] should have the lowest scores for these variables; men in intermediate groups should have greater values, with the peak resting at a Kinsey score of 3); the Absolute Arousal Difference should show a U-shaped distribution (i.e., exclusively heterosexual and exclusively homosexual men should have lower values than bisexual-identified men).

The reason for emphasising these measurements is that they doesn’t completely trust self-report (while agreeing it is valuable)

However, because the scale relied on self-reports, results could not provide definitive evidence for bisexual orientation. For example, surveys have shown that a large proportion of men who identify as gay or homosexual had gone through a previous and transient phase of bisexual identification 

I don’t think anyone (whatever their opinion on bisexuality) would deny that men who lie about sex are real. The problem is treating the physical arousal measurements as basically definitive of bisexuality.  In the clinical trials terminology, the arousal measurement is a relatively hard outcome, but it is a surrogate outcome.

With modern data science (and sufficiently dodgy ethics) there would be other surrogate outcomes that someone has probably explored.  Are there a significant number of men on Tinder who swipe right for both male and female profiles?  Are there many PornHub accounts of men who watch both straight and gay porn? Are there men who have shared a one-bedroom home with both men and women over time?  All of these are clearly reductive: they would give you one-dimensional information about bisexuality, but they are measuring different things and there’s no reason to expect they would agree on how common it is.  The same is true for physiological arousal.  Measuring it can be valuable; the demographics of physiological arousal can be a valid area of study; but it can’t answer the yes/no question.

Some men claim to be attracted to both men and women, and behave as if their claims are true. It turns out, according to this paper, that for some of these men the physiological measurements of arousal show the relationships that you’d expect.  If there weren’t any men whose physiological measurements of arousal show those relationships, that would be an interesting fact, but the real question would be why the measurements don’t fit with the phenomenon of bisexuality.  If you think of this paper as just trying to answer a question about physiological arousal then, ok, that’s the question it tries to answer. And in fact one of the researchers is quoted further down in the NewsHub story saying

“It has always been clear that bisexual men exist in terms of self-identity and behaviour, but many, including myself, were sceptical about their ability to be sexually aroused to both men and women.” 

Contrast that, though, with the paper’s “Significance” section, which starts out

There has long been skepticism among both scientists and laypersons that male bisexual orientation exists.”

Or with the second sentence of the press release:

“The existence of male bisexuality is contested, with skeptics claiming that men who self-identify as bisexual are actually either homosexual or heterosexual.”.

Or with the title of the research paper itself

Robust evidence for bisexual orientation among men

The stretching of the study findings to the headline “Bisexual men are real, study finds” can’t just be blamed on the media.

When we talk about whether Alexander the Great or Shakespeare was bisexual, there are difficulties in even agreeing on the concept over centuries or millennia of social distance.  But I think most people would agree there’s more to the question than what would have happened if you wired them up to a machine and showed them porn.

Briefly

Non-representative sampling!

July 21, 2020

Super Rugby Australia Predictions for Round 4

Team Ratings for Round 4

The basic method is described on my Department home page.
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
Brumbies 3.61 4.67 -1.10
Reds -1.37 -0.31 -1.10
Rebels -4.95 -5.52 0.60
Waratahs -6.08 -7.12 1.00
Force -9.49 -10.00 0.50

Performance So Far

So far there have been 6 matches played, 5 of which were correctly predicted, a success rate of 83.3%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Reds vs. Force Jul 17 31 – 24 13.80 TRUE
2 Waratahs vs. Brumbies Jul 18 23 – 24 -6.10 TRUE

Predictions for Round 4

Here are the predictions for Round 4. 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 Rebels vs. Waratahs Jul 24 Rebels 5.60
2 Force vs. Brumbies Jul 25 Brumbies -8.60

Super Rugby Aotearoa Predictions for Round 7

Team Ratings for Round 7

The basic method is described on my Department home page.
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
Crusaders 15.73 15.15 0.60
Blues 7.09 5.39 1.70
Hurricanes 6.93 8.31 -1.40
Chiefs 5.20 7.94 -2.70
Highlanders 1.61 -0.22 1.80

 

Performance So Far

So far there have been 12 matches played, 8 of which were correctly predicted, a success rate of 66.7%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Hurricanes vs. Blues Jul 18 29 – 27 4.90 TRUE
2 Chiefs vs. Highlanders Jul 19 31 – 33 9.70 FALSE

 

Predictions for Round 7

Here are the predictions for Round 7. 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. Hurricanes Jul 25 Crusaders 13.30
2 Blues vs. Chiefs Jul 26 Blues 6.40

 

NRL Predictions for Round 11

Team Ratings for Round 11

The basic method is described on my Department home page.
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 13.27 12.25 1.00
Storm 13.19 12.73 0.50
Raiders 6.55 7.06 -0.50
Eels 5.18 2.80 2.40
Panthers 4.10 -0.13 4.20
Rabbitohs 2.55 2.85 -0.30
Sharks 2.13 1.81 0.30
Wests Tigers 1.24 -0.18 1.40
Sea Eagles 0.15 1.05 -0.90
Knights -1.57 -5.92 4.40
Dragons -4.19 -6.14 1.90
Cowboys -5.84 -3.95 -1.90
Bulldogs -6.62 -2.52 -4.10
Warriors -8.21 -5.17 -3.00
Broncos -9.64 -5.53 -4.10
Titans -14.29 -12.99 -1.30

 

Performance So Far

So far there have been 80 matches played, 50 of which were correctly predicted, a success rate of 62.5%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Roosters vs. Raiders Jul 16 20 – 24 10.20 FALSE
2 Storm vs. Titans Jul 17 42 – 6 26.40 TRUE
3 Wests Tigers vs. Broncos Jul 17 48 – 0 9.80 TRUE
4 Dragons vs. Bulldogs Jul 18 28 – 22 4.00 TRUE
5 Rabbitohs vs. Knights Jul 18 18 – 20 7.20 FALSE
6 Sea Eagles vs. Eels Jul 18 22 – 18 -4.00 FALSE
7 Sharks vs. Warriors Jul 19 46 – 10 12.70 TRUE
8 Panthers vs. Cowboys Jul 19 22 – 10 11.90 TRUE

 

Predictions for Round 11

Here are the predictions for Round 11. 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 Eels vs. Wests Tigers Jul 23 Eels 5.90
2 Cowboys vs. Sea Eagles Jul 24 Sea Eagles -4.00
3 Broncos vs. Storm Jul 24 Storm -20.80
4 Roosters vs. Warriors Jul 25 Roosters 26.00
5 Sharks vs. Dragons Jul 25 Sharks 6.30
6 Raiders vs. Rabbitohs Jul 25 Raiders 6.00
7 Knights vs. Bulldogs Jul 26 Knights 7.00
8 Titans vs. Panthers Jul 26 Panthers -16.40

 

July 14, 2020

Super Rugby Australia Predictions for Round 3

Team Ratings for Round 3

The basic method is described on my Department home page.
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
Brumbies 4.07 4.67 -0.60
Reds -0.75 -0.31 -0.40
Rebels -4.95 -5.52 0.60
Waratahs -6.54 -7.12 0.60
Force -10.10 -10.00 -0.10

 

Performance So Far

So far there have been 4 matches played, 3 of which were correctly predicted, a success rate of 75%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Rebels vs. Reds Jul 10 18 – 18 0.40 FALSE
2 Waratahs vs. Force Jul 11 23 – 14 7.90 TRUE

 

Predictions for Round 3

Here are the predictions for Round 3. 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 Reds vs. Force Jul 17 Reds 13.80
2 Waratahs vs. Brumbies Jul 18 Brumbies -6.10

 

Super Rugby Aotearoa Predictions for Round 6

Team Ratings for Round 6

The basic method is described on my Department home page.
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
Crusaders 15.73 15.15 0.60
Hurricanes 7.19 8.31 -1.10
Blues 6.84 5.39 1.50
Chiefs 6.02 7.94 -1.90
Highlanders 0.79 -0.22 1.00

 

Performance So Far

So far there have been 10 matches played, 7 of which were correctly predicted, a success rate of 70%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Crusaders vs. Blues Jul 11 26 – 15 13.90 TRUE
2 Hurricanes vs. Highlanders Jul 12 17 – 11 12.00 TRUE

 

Predictions for Round 6

Here are the predictions for Round 6. 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 Hurricanes vs. Blues Jul 18 Hurricanes 4.90
2 Chiefs vs. Highlanders Jul 19 Chiefs 9.70