Posts from July 2025 (22)

July 29, 2025

NRL Predictions for Round 22

Team Ratings for Round 22

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 10.26 9.29 1.00
Panthers 7.03 8.50 -1.50
Roosters 4.33 7.44 -3.10
Dolphins 3.69 -1.96 5.60
Bulldogs 3.67 0.07 3.60
Sharks 3.14 5.10 -2.00
Raiders 2.82 -3.61 6.40
Sea Eagles 1.82 2.97 -1.20
Broncos 0.44 -1.82 2.30
Warriors -0.20 -1.68 1.50
Cowboys -2.17 4.11 -6.30
Dragons -3.85 -4.55 0.70
Knights -4.27 -0.05 -4.20
Rabbitohs -5.19 -4.35 -0.80
Eels -5.42 -3.02 -2.40
Titans -7.02 -5.50 -1.50
Wests Tigers -9.09 -10.97 1.90

 

Performance So Far

So far there have been 156 matches played, 99 of which were correctly predicted, a success rate of 63.5%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Roosters vs. Storm Jul 24 30 – 34 -2.70 TRUE
2 Cowboys vs. Dragons Jul 25 38 – 32 4.40 TRUE
3 Broncos vs. Eels Jul 25 20 – 22 10.00 FALSE
4 Warriors vs. Titans Jul 26 16 – 24 12.10 FALSE
5 Panthers vs. Wests Tigers Jul 26 36 – 2 14.40 TRUE
6 Rabbitohs vs. Sharks Jul 26 12 – 14 -9.10 TRUE
7 Raiders vs. Knights Jul 27 44 – 18 8.50 TRUE
8 Bulldogs vs. Sea Eagles Jul 27 42 – 4 2.00 TRUE

 

Predictions for Round 22

Here are the predictions for Round 22. 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. Storm Jul 31 Storm -12.70
2 Warriors vs. Dolphins Aug 01 Dolphins -0.40
3 Broncos vs. Rabbitohs Aug 01 Broncos 8.60
4 Titans vs. Panthers Aug 02 Panthers -11.10
5 Dragons vs. Raiders Aug 02 Raiders -3.70
6 Sea Eagles vs. Roosters Aug 02 Sea Eagles 0.50
7 Wests Tigers vs. Bulldogs Aug 03 Bulldogs -9.80
8 Sharks vs. Cowboys Aug 03 Sharks 8.30

 

Bunnings NPC Predictions for Week 1

Team Ratings for Week 1

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
Wellington 6.60 6.60 0.00
Bay of Plenty 6.48 6.48 0.00
Waikato 5.46 5.46 -0.00
Taranaki 5.30 5.30 0.00
Canterbury 4.02 4.02 0.00
Tasman 3.49 3.49 0.00
North Harbour 1.50 1.50 0.00
Hawke’s Bay 0.68 0.68 0.00
Auckland -0.04 -0.04 0.00
Counties Manukau -0.26 -0.26 0.00
Otago -1.15 -1.15 0.00
Southland -5.90 -5.90 0.00
Northland -6.54 -6.54 -0.00
Manawatu -13.45 -13.45 -0.00

 

Predictions for Week 1

Here are the predictions for Week 1. 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 Auckland vs. Waikato Jul 31 Waikato -2.50
2 Manawatu vs. North Harbour Aug 01 North Harbour -11.90
3 Wellington vs. Canterbury Aug 02 Wellington 5.60
4 Southland vs. Otago Aug 02 Otago -1.80
5 Taranaki vs. Northland Aug 02 Taranaki 14.80
6 Bay of Plenty vs. Tasman Aug 03 Bay of Plenty 6.00
7 Hawke’s Bay vs. Counties Manukau Aug 03 Hawke’s Bay 3.90

 

Currie Cup Predictions for Round 2

Team Ratings for Round 2

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
Lions 12.37 10.01 2.40
Bulls 7.52 5.94 1.60
Sharks 4.32 6.68 -2.40
Cheetahs 3.25 4.33 -1.10
Pumas -2.69 -4.16 1.50
Western Province -3.52 -1.94 -1.60
Griquas -4.32 -2.85 -1.50
Boland Cavaliers -8.92 -10.00 1.10

 

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 Pumas vs. Griquas Jul 26 49 – 28 2.20 TRUE
2 Lions vs. Sharks Jul 27 46 – 5 6.80 TRUE
3 Western Province vs. Bulls Jul 27 23 – 48 -4.40 TRUE
4 Boland Cavaliers vs. Cheetahs Jul 28 37 – 35 -10.80 FALSE

 

Predictions for Round 2

Here are the predictions for Round 2. 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 Cheetahs vs. Pumas Aug 02 Cheetahs 9.40
2 Lions vs. Western Province Aug 03 Lions 19.40
3 Bulls vs. Sharks Aug 03 Bulls 6.70
4 Griquas vs. Boland Cavaliers Aug 04 Griquas 8.10

 

AFL Predictions for Week 22

Team Ratings for Week 22

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
Adelaide Crows 28.35 2.69 25.70
Western Bulldogs 25.10 18.20 6.90
Geelong Cats 23.36 15.04 8.30
Collingwood 16.11 5.39 10.70
Hawthorn Hawks 15.81 21.95 -6.10
Brisbane Lions 13.33 22.65 -9.30
GWS Giants 13.15 9.08 4.10
Gold Coast Suns 10.14 -6.41 16.60
Fremantle Dockers 8.39 5.99 2.40
Sydney Swans 0.04 12.60 -12.60
Melbourne Demons -2.87 -0.21 -2.70
St Kilda Saints -4.65 0.89 -5.50
Carlton Blues -7.32 5.01 -12.30
Port Adelaide Power -8.98 7.63 -16.60
Essendon Bombers -26.88 -10.15 -16.70
North Melbourne -28.73 -37.08 8.40
Richmond Tigers -28.94 -31.00 2.10
West Coast Eagles -37.82 -34.67 -3.20

 

Performance So Far

So far there have been 170 matches played, 114 of which were correctly predicted, a success rate of 67.1%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Hawthorn Hawks vs. Carlton Blues Jul 24 85 – 61 22.90 TRUE
2 Essendon Bombers vs. Western Bulldogs Jul 25 50 – 143 -45.60 TRUE
3 GWS Giants vs. Sydney Swans Jul 25 102 – 58 12.60 TRUE
4 Gold Coast Suns vs. Brisbane Lions Jul 26 130 – 64 -8.60 FALSE
5 Fremantle Dockers vs. West Coast Eagles Jul 26 126 – 77 45.30 TRUE
6 North Melbourne vs. Geelong Cats Jul 26 49 – 150 -32.40 TRUE
7 Adelaide Crows vs. Port Adelaide Power Jul 26 133 – 35 28.50 TRUE
8 Richmond Tigers vs. Collingwood Jul 27 57 – 93 -47.90 TRUE
9 St Kilda Saints vs. Melbourne Demons Jul 27 96 – 90 -4.20 FALSE

 

Predictions for Week 22

Here are the predictions for Week 22. 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 Western Bulldogs vs. GWS Giants Jul 31 Western Bulldogs 22.90
2 Adelaide Crows vs. Hawthorn Hawks Aug 01 Adelaide Crows 23.50
3 Melbourne Demons vs. West Coast Eagles Aug 02 Melbourne Demons 46.00
4 Gold Coast Suns vs. Richmond Tigers Aug 02 Gold Coast Suns 50.10
5 Sydney Swans vs. Essendon Bombers Aug 02 Sydney Swans 37.90
6 Collingwood vs. Brisbane Lions Aug 02 Collingwood 13.80
7 St Kilda Saints vs. North Melbourne Aug 03 St Kilda Saints 24.10
8 Geelong Cats vs. Port Adelaide Power Aug 03 Geelong Cats 43.30
9 Fremantle Dockers vs. Carlton Blues Aug 03 Fremantle Dockers 26.70

 

July 24, 2025

Currie Cup Predictions for Round 1

Team Ratings for Round 1

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
Lions 10.01 10.01 -0.00
Sharks 6.68 6.68 0.00
Bulls 5.94 5.94 -0.00
Cheetahs 4.33 4.33 -0.00
Western Province -1.94 -1.94 0.00
Griquas -2.85 -2.85 0.00
Pumas -4.16 -4.16 -0.00
Boland Cavaliers -10.00 -10.00 0.00

 

Predictions for Round 1

Here are the predictions for Round 1. 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 Pumas vs. Griquas Jul 26 Pumas 2.20
2 Lions vs. Sharks Jul 27 Lions 6.80
3 Western Province vs. Bulls Jul 27 Bulls -4.40
4 Boland Cavaliers vs. Cheetahs Jul 28 Cheetahs -10.80

 

July 23, 2025

Most commonly reported

From XKCD, the most commonly reported plant and animal on iNaturalist for each US state (click to embiggen)

This is mostly about selection biases of various types: how recognisable the plant or animal is and how interesting.  Saguaro, in Arizona, are not exactly rare, but they aren’t the most commonly seen plant. They are famously associated with the southwest desert and immediately recognisable, so they get reported often.  In other states, the most common plant is genuinely common: yarrow in Montana, California Poppy in California, Amur honeysuckle (sadly) in some Kentucky and Indiana.

So what is it in New Zealand? Looking at the “research-grade” reports, because it’s easier, the most common animal seems to be the kererū, with the pīwakawaka second. Easy to recognise, popular, interesting. For plants, it’s the māhoe, which I wasn’t expecting.

NRL Predictions for Round 21

Team Ratings for Round 21

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 10.16 9.29 0.90
Panthers 6.17 8.50 -2.30
Roosters 4.43 7.44 -3.00
Dolphins 3.69 -1.96 5.60
Sharks 3.53 5.10 -1.60
Sea Eagles 3.22 2.97 0.20
Bulldogs 2.26 0.07 2.20
Raiders 2.04 -3.61 5.60
Broncos 1.03 -1.82 2.80
Warriors 0.68 -1.68 2.40
Cowboys -2.29 4.11 -6.40
Knights -3.48 -0.05 -3.40
Dragons -3.72 -4.55 0.80
Rabbitohs -5.57 -4.35 -1.20
Eels -6.00 -3.02 -3.00
Titans -7.90 -5.50 -2.40
Wests Tigers -8.23 -10.97 2.70

 

Performance So Far

So far there have been 148 matches played, 93 of which were correctly predicted, a success rate of 62.8%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Dolphins vs. Cowboys Jul 17 43 – 24 7.90 TRUE
2 Sharks vs. Roosters Jul 18 31 – 18 0.90 TRUE
3 Panthers vs. Rabbitohs Jul 18 30 – 10 14.10 TRUE
4 Raiders vs. Eels Jul 19 40 – 16 9.70 TRUE
5 Bulldogs vs. Dragons Jul 19 20 – 18 9.80 TRUE
6 Storm vs. Sea Eagles Jul 19 16 – 18 11.20 FALSE
7 Wests Tigers vs. Titans Jul 20 21 – 20 3.00 TRUE
8 Knights vs. Warriors Jul 20 15 – 20 -0.10 TRUE

 

Predictions for Round 21

Here are the predictions for Round 21. 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 Roosters vs. Storm Jul 24 Storm -2.70
2 Cowboys vs. Dragons Jul 25 Cowboys 4.40
3 Broncos vs. Eels Jul 25 Broncos 10.00
4 Warriors vs. Titans Jul 26 Warriors 12.10
5 Panthers vs. Wests Tigers Jul 26 Panthers 14.40
6 Rabbitohs vs. Sharks Jul 26 Sharks -9.10
7 Raiders vs. Knights Jul 27 Raiders 8.50
8 Bulldogs vs. Sea Eagles Jul 27 Bulldogs 2.00

 

AFL Predictions for Week 21

Team Ratings for Week 21

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
Adelaide Crows 23.94 2.69 21.20
Western Bulldogs 21.91 18.20 3.70
Geelong Cats 18.99 15.04 4.00
Brisbane Lions 18.01 22.65 -4.60
Collingwood 17.54 5.39 12.20
Hawthorn Hawks 15.68 21.95 -6.30
GWS Giants 10.91 9.08 1.80
Fremantle Dockers 7.95 5.99 2.00
Gold Coast Suns 5.46 -6.41 11.90
Sydney Swans 2.28 12.60 -10.30
Melbourne Demons -1.64 -0.21 -1.40
Port Adelaide Power -4.56 7.63 -12.20
St Kilda Saints -5.88 0.89 -6.80
Carlton Blues -7.19 5.01 -12.20
Essendon Bombers -23.70 -10.15 -13.60
North Melbourne -24.36 -37.08 12.70
Richmond Tigers -30.37 -31.00 0.60
West Coast Eagles -37.38 -34.67 -2.70

 

Performance So Far

So far there have been 161 matches played, 107 of which were correctly predicted, a success rate of 66.5%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Essendon Bombers vs. GWS Giants Jul 17 56 – 104 -19.50 TRUE
2 Brisbane Lions vs. Western Bulldogs Jul 18 86 – 76 6.20 TRUE
3 Hawthorn Hawks vs. Port Adelaide Power Jul 19 87 – 49 29.10 TRUE
4 Sydney Swans vs. North Melbourne Jul 19 84 – 53 39.70 TRUE
5 Carlton Blues vs. Melbourne Demons Jul 19 78 – 70 -8.10 FALSE
6 West Coast Eagles vs. Richmond Tigers Jul 19 56 – 105 11.90 FALSE
7 Geelong Cats vs. St Kilda Saints Jul 20 113 – 82 37.40 TRUE
8 Collingwood vs. Fremantle Dockers Jul 20 78 – 79 24.30 FALSE
9 Adelaide Crows vs. Gold Coast Suns Jul 20 107 – 46 24.40 TRUE

 

Predictions for Week 21

Here are the predictions for Week 21. 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 Hawthorn Hawks vs. Carlton Blues Jul 24 Hawthorn Hawks 22.90
2 Essendon Bombers vs. Western Bulldogs Jul 25 Western Bulldogs -45.60
3 GWS Giants vs. Sydney Swans Jul 25 GWS Giants 12.60
4 Gold Coast Suns vs. Brisbane Lions Jul 26 Brisbane Lions -8.60
5 Fremantle Dockers vs. West Coast Eagles Jul 26 Fremantle Dockers 45.30
6 North Melbourne vs. Geelong Cats Jul 26 Geelong Cats -32.40
7 Adelaide Crows vs. Port Adelaide Power Jul 26 Adelaide Crows 28.50
8 Richmond Tigers vs. Collingwood Jul 27 Collingwood -47.90
9 St Kilda Saints vs. Melbourne Demons Jul 27 Melbourne Demons -4.20

 

July 21, 2025

Briefly

  • In “where are they now” followup: a 2016 StatsChat post examining a claim that dementia cures were just five years away. They weren’t.
  • Data Strips: A nice lookup at ways to show the distribution of a single numeric variable “in-line”
  • As foreshadowed by XKCD, mobile phone acceleration sensors are now genuinely warning of earthquakes-in-progress (media, research paper)
  • Stuff reports a reported sighting of the South Island kōkako. From the South Island Kōkako Trust (via Mike Dickison), a map just of probable encounters with South Island kōkako (ie, leaving out their large collection of “possible” encounters). They’re everywhere!

    That’s the problem. If they really existed in any significant fraction of the places they’ve been reported, you would expect them to be seen a lot more often including by people with cameras at the ready.  It’s not really feasible for a bird to be on the edge of vanishing, all over the South Island simultaneously, for decades, which is why I think it’s an ex-parrot.
July 19, 2025

Good nitrate, bad nitrate

As you probably have heard, tap water in Gore has been running just above the regulatory maximum of 11.3mg/L of nitrate. Nitrate in high enough doses converts hemoglobin to an inactive form, and babies are more susceptible. There are other risks, but they are more speculative according to the CDC. The risk should be pretty low when the concentration is just above the regulatory limit — that’s the point of regulatory limits — and it’s mostly for babies and pregnant women. Still: not ideal, and  you don’t want to let water standards start to slip.

That first link, though, is from 1News.  A couple of months ago they ran a story headed Seven things to eat or avoid to lower your blood pressure. Number 2 on the list is beetroot, based on its high nitrate content. Yes, the same nitrate that’s in the water in Gore. Beetroot juice contains quite a lot more nitrate. A research paper on sports supplements suggests the effective dose would be about 5 mmol per serving, which translates to a bit more than 300 mg, or more than 25 litres of Gore tapwater.

Obviously there’s difference between sports nerds deliberately drinking beetroot for the nitrates and nitrates turning up as an unwanted contaminant for young and old.  The risks are different, and consent matters. Still, it’s a recurrent irritation that the “nitrates good in massive doses” and “nitrates bad even in small doses” stories don’t get cross-referenced a bit more in the media, and we don’t have a more quantitative approach to the risk.  If we’re supposed to believe it’s actually risky to brush your teeth with water that’s 1% above the regulatory limit, the limit is in the wrong place.