Stats Chat

Team Ratings for Round 25

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 176 matches played, 107 of which were correctly predicted, a success rate of 60.8%.
Here are the predictions for last week’s games.

Predictions for Round 25

Here are the predictions for Round 25. 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 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 7 matches played, 5 of which were correctly predicted, a success rate of 71.4%.
Here are the predictions for last week’s games.

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.

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.

Performance So Far

So far there have been 18 matches played, 11 of which were correctly predicted, a success rate of 61.1%.
Here are the predictions for last week’s games.

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.

There’s a story in New Scientist, and in the NY Daily News, based on this research paper, saying that choosing alternative treatment instead of conventional treatment for cancer is bad for you.

The research is well done: they looked at the most common cancers in the US and found a small set of people who turned down all conventional treatment in favour of ‘alternative’ medicine.  They matched these people on cancer type, age, clinical group stage, what other disease they had, insurance type, race, and year of diagnosis, to a set who did get conventional treatment.   Even after all that matching, there was a big difference in survival.

There are two caveats to the story. First, this is people who turned down all conventional treatment, even surgery. That’s rare. In the database they used, 99.98% of patients received some conventional treatment. It’s much more common for people to receive some or all of the recommended conventional treatment, plus other things — not ‘alternative’ but ‘complementary’ or ‘integrative’ medicine.

Second, the numbers are being misinterpreted.  For example, New Scientist says

Among those with breast cancer, people taking alternative remedies were 5.68 times more likely to die within five years.

The actual figures were 42% and 13%, so about 3.1 times more likely. Here’s the graph

Similarly, the New Scientist story says

They found that people who took alternative medicine were two and half times more likely to die within five years of diagnosis.

The actual figures were 45% and 26%; 1.75 times more likely.

What’s happening is a confusion of rate ratios and actual risks of death; these aren’t the same.  The rate (or hazard) is measured in % per year; the risk is measured in %.  The risk is capped at 100%; the rate doesn’t have an upper limit.   Because of the cap at 100%, risk ratios are mathematically less convenient to model than rate ratios. As a tradeoff, it’s harder to explain your results using rate ratios. The Yale publicity punted on the issue, not mentioning the numbers and leaving reporters to get it wrong.  When this happens, it’s the scientists’ fault, not the reporters’.

Each week, we would like to invite readers of Stats Chat to submit nominations for our Stat of the Week competition and be in with the chance to win an iTunes voucher.

Here’s how it works:

• Anyone may add a comment on this post to nominate their Stat of the Week candidate before midday Friday August 25 2017.
• Statistics can be bad, exemplary or fascinating.
• The statistic must be in the NZ media during the period of August 19 – 25 2017 inclusive.
• Quote the statistic, when and where it was published and tell us why it should be our Stat of the Week.

Next Monday at midday we’ll announce the winner of this week’s Stat of the Week competition, and start a new one.

(more…)

Via GeoNet, a magnitude 4.5 quake south of Dannevirke (blue box)

The squares are reports of shaking. The big cluster is Palmerston North, with secondary clusters in Feilding and Ashhurst: there are more people who felt the quake there because there are more people there.  See also XKCD

Q: Did you see avocado gives you breast cancer?

A: Me?

Q: Well, women with mutations in the BRCA genes, such as Angelina Jolie

A: 🙄

Q: “Women with the faulty ‘Angelina Jolie’ gene should cut back on trendy avocado-based breakfasts to slash their chances of cancer.”

A: No.

Q: So the study wasn’t in women?

A: No. Or avocados.

Q: Mice

A: Not even. Cells in a lab. (press release)

Q: And the avocados?

A: The cells were given extra folate.

Q: And they got cancer?

A: No, they died.

Q: Then why is there a cancer story?

A: The researchers speculated that folate could be part of a future treatment for BRCA-damaged tumours.

Q: That’s kind of not what the Herald says

A: No, but they did get the story from the Daily Mail.

Q: So what do the researchers say about avocados?

A: They don’t mention avocados

Q: Ok, what do they say about folate, then?

A: “The authors caution that no conclusions should be drawn about whether there is any overall effect in a living animal consuming folate.”

Q: So it wasn’t the press release this time

A: No, this looks like it’s down to the Daily Mail.

• “Is it legal for me to violate Terms of Service in order to collect data for a research project?” (in the US). Casey Fiesler on law and ethics of scraping

• My first boss as a statistician. John Simes, has won the University of Sydney Vice-Chancellor’s Award for Excellence. Among other things, he was one of the early proponents of universal clinical trial registration. In 1986 he wrote about the impact of publication bias on treatment choice in cancer.

• Good discussion of virtues and flaws of Sankey diagrams for visualising flows (via Mara Averick).  Also, if you’re interested in data science tools and explanations, you should follow Mara on Twitter @dataandme

• A teaching example based on a baseball/brain cancer ‘cluster’ that didn’t hold up.  Much smaller numbers than the brain injury problems in US football or even rugby, and less prior plausibility.

• Guidelines on “trusted data use” from the NZ Data Futures partnership

• The US is having a census in 2020 — the Constitution says so. It could be a mess.  Ours, next year, looks to be in better shape.

• How much copper do you get out of a copper mine: visualisation

• It’s not just New Zealanders who have order of magnitude-and-units problems. From The New Yorker, via Felix Salmon
  

It’s pretty standard that headlines (and often politicians) overstate the likely effect of road safety precautions — eg, the claim that lowering the blood alcohol limit would prevent all deaths in which drivers were over the limit, which it obviously won’t.

This is from the Herald’s front page.

On the left, the number 94 is the number of people who died in crashes while not wearing seatbelts. On the right (and in the story), the we find that this is about a third of all the deaths. It’s quite possible to wear a seatbelt and still die in a crash.

Looking for research, I found this summary from a UK organisation that does independent reviews on road safety issues. They say seatbelts in front seats prevent about 45% of fatal injuries in front seat passengers. For rear-seat passengers the data are less clear.

So, last year probably about 45 people died on our roads because they weren’t wearing seatbelts. That’s a big enough number to worry about: we don’t need to double it.

Q: Did you see that using emoji in work-related emails could hurt your career?

A:😕

Q: Yes, it’s apparently a common email mistake

A: 😯

Q: The 549 study participants from 29 countries “were asked to read a work-related email from an unknown person, and were asked to evaluate the competence and warmth of the sender”

A:🤔 💻 🇹🇷

Q: Yes, they were from Amazon’s Mechanical Turk (paper)

A: 😕

Q: Ok, so they weren’t really work-related emails from someone they’d never met, in another country. But the participants were told to pretend they were.

A: 🙁

Q: And it undermined information sharing

A: 😕 👥 💻 🤐 ?

Q: The email replies to messages with emoji had fewer words in them on average

A: 🤔 🙂

Q: Ok, yes, that’s not necessarily a bad thing.

A: 👩‍💼👨🏽‍💼🗣 😀 ?

Q: Is it really common to use emoji in business email? Yes, they say nearly 20% of emails in one previous sample included emoji.

A: 🙄 🇬🇸🇸🇱🇸🇬🇸🇳🇸🇦 👩‍💼👨🏽‍💼🗣 😀 ?

Q: No, I suppose that wasn’t international emails between people who had never met or corresponded before.

A: 🙄

Q: So using emoji in formal emails to a complete stranger could be a bad idea?

A: 😴