Posts from February 2025 (14)

February 18, 2025

Surprises in data

When you get access to some data, a first step is to see if you understand it: do the variables measure what you expect, are there surprising values, and so on.  Often, you will be surprised by some of the results. Almost always this is because the data mean something a bit different from what you expected. Sometimes there are errors. Occasionally there is outright fraud.

Elon Musk and DOG-E have been looking at US Social Security data. They created a table of Social Security-eligible people not recorded as dead and noticed that (a) some of them were surprisingly old, and (b) the total added up to more than the US population.

That’s a good first step, as I said. The next step is to think about possible explanations (as Dan Davies says: “if you don’t make predictions, you won’t know when to be surprised”). The first two I thought of were people leaving the US after working long enough to be eligible for Social Security (like, for example, me) and missing death records for old people (the vital statistics records weren’t as good in the 19th century as they are now).

After that, the proper procedure is to ask someone or look for some documentation, rather than just to go with your first guess.  It’s quite likely that someone else has already observed the existence of records with unreasonable ages and looked for an explanation.

In this case, one would find (eg, by following economist Justin Wolfers) a 2023 report “Numberholders Age 100 or Older Who Did Not Have Death Information on the Numident” (PDF), a report by the Office of the Inspector General, which said that the very elderly ‘vampires collecting Social Security’ were neither vampires nor collecting Social Security, but were real people whose deaths hadn’t been recorded.   This was presumably a follow-up to a 2015 story where identity fraud was involved — but again, the government wasn’t losing money, because it wasn’t paying money out to dead people.

The excess population at younger years isn’t explained by this report, but again, the next step is to see what is already known by the people who spend their whole careers working with the data, rather than to decide  the explanation is the first thing that comes to mind.

February 17, 2025

Briefly

February 12, 2025

United Rugby Championship Predictions for Week 11

Team Ratings for Week 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
Leinster 15.79 12.09 3.70
Bulls 9.00 8.83 0.20
Glasgow 8.52 9.39 -0.90
Munster 4.82 9.28 -4.50
Stormers 3.99 6.75 -2.80
Lions 3.41 6.73 -3.30
Edinburgh 1.95 0.09 1.90
Ulster 1.49 2.52 -1.00
Sharks 1.40 -2.94 4.30
Cheetahs 0.80 0.80 0.00
Connacht -0.91 -0.76 -0.10
Ospreys -2.29 -2.51 0.20
Scarlets -3.54 -10.65 7.10
Benetton -4.69 1.02 -5.70
Southern Kings -6.52 -6.52 0.00
Cardiff Rugby -7.46 -2.55 -4.90
Zebre -11.11 -16.17 5.10
Dragons -14.65 -15.41 0.80

 

Performance So Far

So far there have been 78 matches played, 58 of which were correctly predicted, a success rate of 74.4%.
Here are the predictions for last week’s games.

Game Date Score Prediction Correct
1 Stormers vs. Bulls Feb 09 32 – 33 -2.90 TRUE

 

Predictions for Week 11

Here are the predictions for Week 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 Edinburgh vs. Zebre Feb 15 Edinburgh 18.60
2 Ospreys vs. Leinster Feb 15 Leinster -12.60
3 Lions vs. Stormers Feb 16 Lions 1.90
4 Bulls vs. Sharks Feb 16 Bulls 10.10
5 Benetton vs. Ulster Feb 16 Ulster -0.70
6 Munster vs. Scarlets Feb 16 Munster 13.90
7 Connacht vs. Cardiff Rugby Feb 16 Connacht 12.00
8 Dragons vs. Glasgow Feb 17 Glasgow -17.70

 

Super Rugby 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
Blues 14.92 14.92 0.00
Chiefs 11.43 11.43 0.00
Hurricanes 10.97 10.97 -0.00
Crusaders 8.99 8.99 0.00
Brumbies 6.19 6.19 -0.00
Reds 1.35 1.35 0.00
Highlanders -2.50 -2.50 0.00
Waratahs -5.17 -5.17 0.00
Western Force -6.41 -6.41 0.00
Fijian Drua -7.98 -7.98 -0.00
Moana Pasifika -11.25 -11.25 -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 Crusaders vs. Hurricanes Feb 14 Crusaders 1.50
2 Waratahs vs. Highlanders Feb 14 Waratahs 1.30
3 Fijian Drua vs. Brumbies Feb 15 Brumbies -10.70
4 Blues vs. Chiefs Feb 15 Blues 7.00
5 Western Force vs. Moana Pasifika Feb 15 Western Force 8.80