Posts from September 2018 (22)

• Are we being misled by precision medicine? New York Times
• When people search for a phrase that does not have natural informative results, it’s easy for manipulators to control the results. Take, for example, “did the Holocaust exist?” danah boyd on search and media manipulation
• Should the Norfolk (UK) police be using a predictive model to decide whether a burglary is worth spending effort on? IEEE Spectrum is somewhat more negative than I would be.
• Interesting piece at Slate about a story relating social media and hate crimes in Germany
• Correlations can be confusing. This, from David Hood on Twitter, shows that countries where more people get the recommended amount of exercise have more deaths from heart disease, cancer, lung disease, diabetes.  That’s also what trends over time would say.  Presumably the (real) benefits of exercise are smaller than the benefits of wealth and modern health care, but it’s a neat example.   Note that this isn’t chance correlation in small samples with many variables to choose from, unlike the famous spurious correlations website
  

There was a story on Radio NZ last night, and then in other places

The research is the first in the world to measure the impact of taking numerous medications on fractures in the elderly.

Its findings show elderly people taking several high-risk medications for sleeping, pain or incontinence are twice as likely to fall and break bones as those taking no medication.

As the story says, overmedication in elderly people is known to be a problem — people get put on medications and then not taken off them, and there are interactions, and it’s not good.  Some — even many– of the drugs are necessary, of course, but these researchers aren’t the only people who think there should be more regular review of what all medications someone is taking.

This research is trying to quantify the impact on falls and fractures, using a large NZ data set of everyone in NZ who was being evaluated for publicly funded long-term community services or aged residential care.  Together with the high-quality NZ prescription data, it’s a good opportunity to look at a large enough group of people to measure fractures.

The media stories all seem to come from the Otago press release. The press release doesn’t include a link to the research paper. It doesn’t even give the journal name. The implication that no-one who reads the story could possibly care about the details is a bit insulting.

I’m assuming the research paper is this one, which is new and has the right topic and authors. The analysis is a bit tricky: a lot of people die without having fractures, and you have to decide how to count them in the denominator over time.  They did a sensible analysis, if not exactly the one I would have done.

There’s one problem, though: that paper says, in the Results section of the Abstract:

The estimated subhazard ratio was 1.52 (95% confidence interval: 1.28, 1.81) for those with DBI>3 compared with those with DBI=0 in the adjusted analysis.

That is, the paper’s best estimate is a 50% higher rate of fractures in people taking multiple potentially-risky drugs compared to none. 50% higher is still a problem — they estimate that about 1 in 8 fractures could be prevented if everyone could be taken off these drugs (which, of course, not every one can) — but 50% higher isn’t twice as high, and I couldn’t find the “twice as high” number in the paper.

Team Ratings for Finals Week 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.

Performance So Far

So far there have been 196 matches played, 122 of which were correctly predicted, a success rate of 62.2%.
Here are the predictions for last week’s games.

Predictions for Finals Week 2

Here are the predictions for Finals Week 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.

Team Ratings for Round 5

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.

Performance So Far

So far there have been 30 matches played, 19 of which were correctly predicted, a success rate of 63.3%.
Here are the predictions for last week’s games.

Predictions for Round 5

Here are the predictions for Round 5. 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.

Team Ratings for Round 5

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.

Note that Cheetahs2 refers the Cheetahs team when there is a Pro14 match. The assumption is that the team playing in the Pro14 is the top team and the Currie Cup team is essentially a second team.

Performance So Far

So far there have been 11 matches played, 9 of which were correctly predicted, a success rate of 81.8%.
Here are the predictions for last week’s games.

Predictions for Round 5

Here are the predictions for Round 5. 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.

Ben Goldacre on Twitter, about a “heart age test” that “has so far told eight in ten people that they are at higher risk of serious illness because their heart is prematurely aged.”

“that’s either a fumbled implementation turning coefficients into automated patient advice; or it’s a radical new NHS screening programme announced, oddly, only to individual members of the public, one by one, through an app”

Screening is always easy to sell, so it’s useful to remember a sound-bite: “Screening is the opposite of treatment: you come in healthy and go out sick”

From the New York Times

For the first time, we’ll publish our poll results and display them in real time, from start to finish, respondent by respondent. No media organization has ever tried something like this, and we hope to set a new standard of transparency. You’ll see the poll results at the same time we do. You’ll see our exact assumptions about who will turn out, where we’re calling and whether someone is picking up. You’ll see what the results might have been had we made different choices.

Team Ratings for Finals 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.

Performance So Far

So far there have been 192 matches played, 119 of which were correctly predicted, a success rate of 62%.
Here are the predictions for last week’s games.

Predictions for Finals Week 1

Here are the predictions for Finals 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.

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.

Performance So Far

So far there have been 22 matches played, 14 of which were correctly predicted, a success rate of 63.6%.
Here are the predictions for last week’s games.

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.

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.
Note that Cheetahs2 refers the Cheetahs team when there is a Pro14 match. The assumption is that the team playing in the Pro14 is the top team and the Currie Cup team is essentially a second team.

Performance So Far

So far there have been 8 matches played, 6 of which were correctly predicted, a success rate of 75%.
Here are the predictions for last week’s games.

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.