Posts filed under General (2880)

June 3, 2025

Super Rugby Predictions for the Quarter-finals

Team Ratings for the Quarter-finals

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
Chiefs 14.37 11.43 2.90
Blues 11.28 14.92 -3.60
Hurricanes 10.35 10.97 -0.60
Crusaders 9.94 8.99 1.00
Brumbies 6.35 6.19 0.20
Reds 2.76 1.35 1.40
Highlanders -2.95 -2.50 -0.40
Waratahs -6.93 -5.17 -1.80
Western Force -7.15 -6.41 -0.70
Fijian Drua -8.52 -7.98 -0.50
Moana Pasifika -8.96 -11.25 2.30

 

Performance So Far

So far there have been 77 matches played, 55 of which were correctly predicted, a success rate of 71.4%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Highlanders vs. Chiefs May 30 24 – 41 -13.30 TRUE
2 Brumbies vs. Crusaders May 30 31 – 33 0.80 FALSE
3 Blues vs. Waratahs May 31 46 – 6 20.70 TRUE
4 Hurricanes vs. Moana Pasifika May 31 64 – 12 20.60 TRUE
5 Reds vs. Fijian Drua May 31 52 – 7 12.50 TRUE

 

Predictions for the Quarter-finals

Here are the predictions for the Quarter-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. Reds Jun 06 Crusaders 11.20
2 Chiefs vs. Blues Jun 07 Chiefs 6.60
3 Brumbies vs. Hurricanes Jun 07 Brumbies 0.00

 

Rugby Premiership Predictions for the Semi-finals

Team Ratings for the Semi-finals

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
Bath 10.75 5.55 5.20
Sale Sharks 6.93 4.73 2.20
Leicester Tigers 5.49 3.27 2.20
Saracens 5.27 9.68 -4.40
Gloucester 4.57 -9.04 13.60
Bristol 3.89 9.58 -5.70
Northampton Saints -1.27 7.50 -8.80
Harlequins -2.64 -2.73 0.10
Exeter Chiefs -4.28 1.23 -5.50
Newcastle Falcons -17.96 -19.02 1.10

 

Performance So Far

So far there have been 90 matches played, 62 of which were correctly predicted, a success rate of 68.9%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Bristol vs. Harlequins Jun 01 52 – 26 9.80 TRUE
2 Exeter Chiefs vs. Sale Sharks Jun 01 26 – 30 -4.90 TRUE
3 Gloucester vs. Northampton Saints Jun 01 41 – 26 11.70 TRUE
4 Leicester Tigers vs. Newcastle Falcons Jun 01 42 – 20 31.90 TRUE
5 Saracens vs. Bath Jun 01 36 – 26 -1.20 FALSE

 

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 Bath vs. Bristol Jun 07 Bath 13.40
2 Leicester Tigers vs. Sale Sharks Jun 08 Leicester Tigers 5.10

 

NRL Predictions for Round 14

Team Ratings for Round 14

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 9.93 9.29 0.60
Panthers 5.33 8.50 -3.20
Sharks 4.93 5.10 -0.20
Roosters 4.83 7.44 -2.60
Sea Eagles 3.47 2.97 0.50
Bulldogs 2.31 0.07 2.20
Cowboys 1.62 4.11 -2.50
Raiders 0.92 -3.61 4.50
Dolphins 0.17 -1.96 2.10
Warriors -0.52 -1.68 1.20
Broncos -1.72 -1.82 0.10
Dragons -3.23 -4.55 1.30
Knights -3.81 -0.05 -3.80
Eels -4.13 -3.02 -1.10
Rabbitohs -4.21 -4.35 0.10
Titans -7.09 -5.50 -1.60
Wests Tigers -8.80 -10.97 2.20

 

Performance So Far

So far there have been 100 matches played, 54 of which were correctly predicted, a success rate of 54%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Dragons vs. Knights May 30 20 – 6 2.40 TRUE
2 Titans vs. Storm May 31 16 – 28 -14.40 TRUE
3 Cowboys vs. Wests Tigers May 31 32 – 28 14.50 TRUE
4 Sea Eagles vs. Broncos May 31 34 – 6 6.30 TRUE
5 Rabbitohs vs. Warriors Jun 01 30 – 36 0.50 FALSE
6 Panthers vs. Eels Jun 01 18 – 10 9.70 TRUE
7 Roosters vs. Raiders Jun 01 24 – 26 7.90 FALSE

 

Predictions for Round 14

Here are the predictions for Round 14. 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. Sea Eagles Jun 05 Sea Eagles -4.30
2 Storm vs. Cowboys Jun 06 Storm 11.30
3 Dolphins vs. Dragons Jun 06 Dolphins 6.40
4 Sharks vs. Warriors Jun 07 Sharks 8.90
5 Broncos vs. Titans Jun 07 Broncos 8.40
6 Raiders vs. Rabbitohs Jun 08 Raiders 8.10
7 Wests Tigers vs. Panthers Jun 08 Panthers -11.10
8 Bulldogs vs. Eels Jun 09 Bulldogs 9.40

 

AFL Predictions for Week 14

 

Team Ratings for Week 14

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
Western Bulldogs 22.28 18.20 4.10
Collingwood 22.11 5.39 16.70
Geelong Cats 20.09 15.04 5.10
Adelaide Crows 19.96 2.69 17.30
Brisbane Lions 13.33 22.65 -9.30
Hawthorn Hawks 10.53 21.95 -11.40
Fremantle Dockers 8.32 5.99 2.30
GWS Giants 5.17 9.08 -3.90
Gold Coast Suns 4.91 -6.41 11.30
Carlton Blues 0.91 5.01 -4.10
Sydney Swans -2.38 12.60 -15.00
St Kilda Saints -3.28 0.89 -4.20
Melbourne Demons -3.62 -0.21 -3.40
Port Adelaide Power -7.22 7.63 -14.90
Essendon Bombers -12.74 -10.15 -2.60
North Melbourne -27.96 -37.08 9.10
Richmond Tigers -30.36 -31.00 0.60
West Coast Eagles -32.46 -34.67 2.20

 

Performance So Far

So far there have been 105 matches played, 66 of which were correctly predicted, a success rate of 62.9%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Brisbane Lions vs. Essendon Bombers May 29 90 – 72 40.50 TRUE
2 Collingwood vs. Hawthorn Hawks May 30 107 – 56 5.40 TRUE
3 Gold Coast Suns vs. Fremantle Dockers May 31 64 – 75 10.90 FALSE
4 GWS Giants vs. Richmond Tigers May 31 80 – 77 53.20 TRUE
5 Sydney Swans vs. Adelaide Crows May 31 41 – 131 -0.40 TRUE
6 Melbourne Demons vs. St Kilda Saints Jun 01 63 – 91 4.30 FALSE
7 West Coast Eagles vs. Geelong Cats Jun 01 73 – 116 -41.10 TRUE

 

Predictions for Week 14

Here are the predictions for Week 14. 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. Hawthorn Hawks Jun 05 Western Bulldogs 11.80
2 Adelaide Crows vs. Brisbane Lions Jun 06 Adelaide Crows 17.60
3 Richmond Tigers vs. Sydney Swans Jun 07 Sydney Swans -17.00
4 Geelong Cats vs. Gold Coast Suns Jun 07 Geelong Cats 19.20
5 GWS Giants vs. Port Adelaide Power Jun 07 GWS Giants 23.40
6 North Melbourne vs. West Coast Eagles Jun 08 West Coast Eagles -6.50
7 Carlton Blues vs. Essendon Bombers Jun 08 Carlton Blues 13.60
8 Melbourne Demons vs. Collingwood Jun 09 Collingwood -25.70

 

May 28, 2025

Typical wedding

From RNZ this week

The Wedding Planner director Susannah Reid said in 2023 $58,000 was a typical budget for a wedding across New Zealand but this year, the average cost was more like $87,600.

As we’ve seen in the past, this use of ‘typical’ by people in the wedding industry doesn’t have a lot to do with how the word is normally used.  In that post, in 2014, the typical value from the marital-industrial complex was $30,000.  In 2025 dollars that’s about $40,000, so apparently the real cost of “typical” weddings has more than doubled over the time StatsChat has been running.

Radio NZ also have this week: How New Zealand couples saved on their wedding (and what they splurged on). The most expensive wedding here is less than a quarter of the “typical” budget; the others are less than 10%.

If you think about it, estimating the actual cost of a typical wedding is quite hard.  Technically it’s not that difficult: the government keeps track of marriages, so you could do a survey of a sample of marriages and ask people, but the Births, Deaths, and Marriages people will only let you browse arbitrary marriages from the distant past. Contemporary marriages are public records, but public access to them is by name rather than just by year.   If you don’t have a genuine sample, you’ll tend to notice big weddings more than small ones.

May 27, 2025

Super Rugby Predictions for the Quarter-finals

Team Ratings for the Quarter-finals

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
Chiefs 14.11 11.43 2.70
Blues 10.53 14.92 -4.40
Crusaders 9.74 8.99 0.80
Hurricanes 9.24 10.97 -1.70
Brumbies 6.54 6.19 0.30
Reds 1.63 1.35 0.30
Highlanders -2.69 -2.50 -0.20
Waratahs -6.19 -5.17 -1.00
Western Force -7.15 -6.41 -0.70
Fijian Drua -7.39 -7.98 0.60
Moana Pasifika -7.85 -11.25 3.40

 

Performance So Far

So far there have been 72 matches played, 51 of which were correctly predicted, a success rate of 70.8%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Crusaders vs. Highlanders May 23 15 – 12 17.10 TRUE
2 Reds vs. Hurricanes May 23 27 – 31 -3.60 TRUE
3 Chiefs vs. Moana Pasifika May 24 85 – 7 22.00 TRUE
4 Western Force vs. Waratahs May 24 17 – 22 3.30 FALSE

 

Predictions for the Quarter-finals

Here are the predictions for the Quarter-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 Highlanders vs. Chiefs May 30 Chiefs -13.30
2 Brumbies vs. Crusaders May 30 Brumbies 0.80
3 Blues vs. Waratahs May 31 Blues 20.70
4 Hurricanes vs. Moana Pasifika May 31 Hurricanes 20.60
5 Reds vs. Fijian Drua May 31 Reds 12.50

 

NRL Predictions for Round 13

Team Ratings for Round 13

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 10.12 9.29 0.80
Panthers 5.47 8.50 -3.00
Roosters 5.33 7.44 -2.10
Sharks 4.93 5.10 -0.20
Sea Eagles 2.53 2.97 -0.40
Bulldogs 2.31 0.07 2.20
Cowboys 2.14 4.11 -2.00
Raiders 0.42 -3.61 4.00
Dolphins 0.17 -1.96 2.10
Broncos -0.78 -1.82 1.00
Warriors -0.88 -1.68 0.80
Knights -3.24 -0.05 -3.20
Dragons -3.79 -4.55 0.80
Rabbitohs -3.85 -4.35 0.50
Eels -4.27 -3.02 -1.30
Titans -7.28 -5.50 -1.80
Wests Tigers -9.33 -10.97 1.60

 

Performance So Far

So far there have been 93 matches played, 49 of which were correctly predicted, a success rate of 52.7%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Bulldogs vs. Dolphins May 22 8 – 44 8.50 FALSE
2 Eels vs. Sea Eagles May 23 30 – 10 -6.00 FALSE
3 Panthers vs. Knights May 24 6 – 25 11.20 FALSE
4 Roosters vs. Sharks May 24 42 – 16 1.30 TRUE
5 Warriors vs. Raiders May 25 10 – 16 3.10 FALSE

 

Predictions for Round 13

Here are the predictions for Round 13. 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. Knights May 30 Dragons 2.40
2 Titans vs. Storm May 31 Storm -14.40
3 Cowboys vs. Wests Tigers May 31 Cowboys 14.50
4 Sea Eagles vs. Broncos May 31 Sea Eagles 6.30
5 Rabbitohs vs. Warriors Jun 01 Rabbitohs 0.50
6 Panthers vs. Eels Jun 01 Panthers 9.70
7 Roosters vs. Raiders Jun 01 Roosters 7.90

 

AFL Predictions for Week 13

Team Ratings for Week 13

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
Western Bulldogs 22.28 18.20 4.10
Geelong Cats 19.87 15.04 4.80
Collingwood 19.03 5.39 13.60
Brisbane Lions 15.02 22.65 -7.60
Adelaide Crows 14.48 2.69 11.80
Hawthorn Hawks 13.62 21.95 -8.30
GWS Giants 8.51 9.08 -0.60
Fremantle Dockers 6.67 5.99 0.70
Gold Coast Suns 6.57 -6.41 13.00
Sydney Swans 3.10 12.60 -9.50
Carlton Blues 0.91 5.01 -4.10
Melbourne Demons -1.32 -0.21 -1.10
St Kilda Saints -5.58 0.89 -6.50
Port Adelaide Power -7.22 7.63 -14.90
Essendon Bombers -14.43 -10.15 -4.30
North Melbourne -27.96 -37.08 9.10
West Coast Eagles -32.23 -34.67 2.40
Richmond Tigers -33.70 -31.00 -2.70

 

Performance So Far

So far there have been 98 matches played, 61 of which were correctly predicted, a success rate of 62.2%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Geelong Cats vs. Western Bulldogs May 22 127 – 113 6.90 TRUE
2 Essendon Bombers vs. Richmond Tigers May 23 81 – 58 18.10 TRUE
3 Carlton Blues vs. GWS Giants May 24 82 – 110 8.50 FALSE
4 Hawthorn Hawks vs. Brisbane Lions May 24 60 – 93 16.20 FALSE
5 North Melbourne vs. Collingwood May 24 63 – 108 -47.60 TRUE
6 Fremantle Dockers vs. Port Adelaide Power May 24 100 – 51 20.80 TRUE
7 Adelaide Crows vs. West Coast Eagles May 25 128 – 62 55.10 TRUE
8 Melbourne Demons vs. Sydney Swans May 25 131 – 78 -0.50 FALSE
9 St Kilda Saints vs. Gold Coast Suns May 25 61 – 80 2.10 FALSE

 

Predictions for Week 13

Here are the predictions for Week 13. 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 Brisbane Lions vs. Essendon Bombers May 29 Brisbane Lions 40.50
2 Collingwood vs. Hawthorn Hawks May 30 Collingwood 5.40
3 Gold Coast Suns vs. Fremantle Dockers May 31 Gold Coast Suns 10.90
4 GWS Giants vs. Richmond Tigers May 31 GWS Giants 53.20
5 Sydney Swans vs. Adelaide Crows May 31 Adelaide Crows -0.40
6 Melbourne Demons vs. St Kilda Saints Jun 01 Melbourne Demons 4.30
7 West Coast Eagles vs. Geelong Cats Jun 01 Geelong Cats -41.10

 

May 24, 2025

Redrawing a graph

Newsroom has an article about tertiary funding in the new budget.  There’s a graph showing how the government fee cap and inflation have competed over the past few years. The graph in the article (ignoring the impact of a fee-free year) is

I find this a bit hard to interpret — it’s not easy to see the cumulative effect of the two changes and work out whether fees have shot ahead or lagged behind.  I think this is clearer, showing the cumulative effect of inflation and the (maximum) fee increase; the highlight is the two Covid border-closure years.

We can see that fees had increased in real terms but had now fallen behind inflation. Based (obviously) on a projection for 2026, fees might be slightly ahead again.

Another option is to use the inflation series to deflate the fee cap and just show the real-terms fee changes. Again, fees were up in real terms, then down, and are right at the 2014 level. Again, this ignores the impact of a fee-free year, which will depend on when one started uni.

What I think this shows is that adding up yearly changes (especially multiplicative ones) in your head is hard, and it’s probably harder than the opposite task of estimating changes in slopes.  If you need both scales, you might be better off with a cumulative graph.   The big disadvantage of a cumulative graph is that the visual impression can be quite sensitive to when you start adding.

 

May 20, 2025

How many coffees is a house?

RadioNZ have How many years would you have to skip coffee to save enough to buy a house?

The story correctly says (a) a lot, even if house prices didn’t go up, and (b) that’s not really the question.

There’s one point they miss  which is important to a lot of the narrative on house prices and saving (perhaps because this is a personal finance article, not a housing prices article).

The reason for housing unaffordability isn’t that Kiwis aren’t spending enough on housing.  You could imagine a world where housing was readily available and affordable, but people in general, or some group of people, couldn’t buy houses because they were spending all their money on beer and holidays and not saving anything for a deposit. In a world like that, advising people to save might be useful (if they listened).

That’s not the problem in New Zealand.  Kiwis, collectively, are spending far too much on housing. If one person gave up coffee or avocado toast  to save faster it might help them a little bit.  If we collectively gave up coffee and avocado toast to save faster, housing prices would just increase faster to compensate.