Posts from May 2019 (27)

From Stuff

Ten thousand is often touted as the golden number of steps required in a day to live a healthy life.

It’s a goal many Kiwis don’t reach, with one survey from the Ministry of Transport highlighting 80 per cent of respondents don’t walk more than 100 metres a day.

But new research has found the sweet spot to be significantly lower, especially for older women wanting to live longer.

The study – published in JAMA Internal Medicine by researchers from Harvard Medical School – found just 7500 steps a day, for women aged over 70, could cut their risk of death.

This is a good description of the study — and it even links to the research.  There are two aspects that are not really clear in the story, but they’re not really clear in the text of the research paper either.

The researchers asked 18000 women over 60 to wear accelerometers (like Fitbits, but less cool) for a week, to measure how much they walked, and then waited for a bit more than four years to see who died.  Women who walked more were less likely to die during that period. Here’s the graph comparing rates of death by amount of walking.  The blue curve is the study estimate of the reduction in rate of death, but the shaded area is an uncertainty interval — the data are consistent with the curve being basically anywhere in the shaded region

As you can see, the estimated curve flattens out at about 7500 steps per day.  If we just looked at the blue line we’d say any women who walks less than 7500 steps per day could cut her risk of death by walking even a bit more, but that 7500 is the maximum that’s worthwhile. Looking at the shaded area shows that we really don’t have much idea about what happened to women who walked more than 7500 steps. Their risk could have been quite a bit lower, or about the same, or higher.  The problem is that only 49 of the women who walked more than 7500 steps per day ended up dying during the study; that’s great for them, but it’s a real limitation for the statistical analysis.

Also, you might worry (you should worry) which way cause and effect goes.  The headline would sound less interesting if it said women within four years of dying walked less than women with a longer life expectancy, but the correlation is the same either way. I’d guess it’s mixture of both: walking does make you healthier, but being healthier also makes you walk more.

PS: I should note that the Stuff journalist, Brittney Deguara, also got the story on WHO classification of ‘burnout’ correct (it’s not being listed as a medical condition), vs the somewhat misleading story in the Herald that begins “Burnout” is officially a disease, according to the World Health Organisation.

From Deloitte’s NZ budget infographic, via Siouxsie Wiles

This is weird as a pie chart because the two sections aren’t components of a whole (which is how pies, or Camembert, work). It’s also strange that the new operating expenditure is shown as a bite out of expenses, when it actually makes expenses larger than they would be without it.

On top of all that, the divisions of the apple aren’t actually in proportion to the numbers.  This is what a pie chart with those numbers would look like: the difference between the halves is nearly invisible.

• Chris Knox, at the Herald:
• Andy Fyers, at Stuff
• Deloitte

Any more?

Team Ratings for Round 16

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 98 matches played, 65 of which were correctly predicted, a success rate of 66.3%.
Here are the predictions for last week’s games.

Predictions for Round 16

Here are the predictions for Round 16. 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 the Final

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 134 matches played, 91 of which were correctly predicted, a success rate of 67.9%.
Here are the predictions for last week’s games.

Predictions for the Final

Here are the predictions for the Final. 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 12

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 88 matches played, 58 of which were correctly predicted, a success rate of 65.9%.
Here are the predictions for last week’s games.

Predictions for Round 12

Here are the predictions for Round 12. 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 15

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 91 matches played, 59 of which were correctly predicted, a success rate of 64.8%.
Here are the predictions for last week’s games.

Predictions for Round 15

Here are the predictions for Round 15. 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 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.

Performance So Far

So far there have been 132 matches played, 89 of which were correctly predicted, a success rate of 67.4%.
Here are the predictions for last week’s games.

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.

Team Ratings for the Final

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 151 matches played, 115 of which were correctly predicted, a success rate of 76.2%.
Here are the predictions for last week’s games.

Predictions for the Final

Here are the predictions for the Final. 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 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.

Performance So Far

So far there have been 80 matches played, 55 of which were correctly predicted, a success rate of 68.8%.
Here are the predictions for last week’s games.

Predictions for Round 11

Here are the predictions for Round 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.