Posts from April 2012 (50)

Statistician and marine biologist Marti Anderson from Massey University talked to Kim Hill on Radio New Zealand National about studying complex biological systems of species. The 18 minute long MP3 recording of the interview is now available online here, or listen below:

Marti was a part of the Department of Statistics at the University of Auckland for many years.

The recent Sky City stories illustrate an interesting division in media reports of gambling

• Poker machine stories are about losing money
• Lottery stories are about winning money.

The Herald says “Lower drinking age blamed for high rate of youth deaths” and quotes a University of Auckland researcher, Dr Anne Beautrais,

“Addressing alcohol use and binge drinking in young people in New Zealand is one of the most obvious avenues to reducing both suicide and traffic mortality.”

Dr Beautrais points out that the high suicide rate in NZ can’t just be attributed to better reporting than in other countries. The overall youth death rate is high in NZ, and while diagnosis of suicide might be variable, diagnosis of death is pretty reliable.   That all makes sense.   Road deaths are an important component, and there you’d expect lowering the drinking age to have some effect.

I’m less convinced by the drinking-age argument  for suicide.  One reason is the US experience, where the Reagan administration raised the drinking age to 21 in 1984.  The graph below (data from CDC) shows US male suicide rates by age group across time, and there’s really no sign of a decrease in 1984

Due to no entries being posted in last week’s Stat of the Week competition, there is no winner this week. Make sure you add your nominations in for this week’s competition!

If you’d like to comment on or debate any of this week’s Stat of the Week nominations, please do so below!

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 May 4 2012.
• Statistics can be bad, exemplary or fascinating.
• The statistic must be in the NZ media during the period of April 28-May 4 2012 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.

The fine print:

• Judging will be conducted by the blog moderator in liaison with staff at the Department of Statistics, The University of Auckland.
• The judges’ decision will be final.
• The judges can decide not to award a prize if they do not believe a suitable statistic has been posted in the preceeding week.
• Only the first nomination of any individual example of a statistic used in the NZ media will qualify for the competition.
• Employees (other than student employees) of the Statistics department at the University of Auckland are not eligible to win.
• The person posting the winning entry will receive a $20 iTunes voucher.
• The blog moderator will contact the winner via their notified email address and advise the details of the $20 iTunes voucher to that same email address.
• The competition will commence Monday 8 August 2011 and continue until cancellation is notified on the blog.

The first international competition to recognize outstanding work in the growing field of data journalism, the Data Journalism Awards, has just announced the 58 nominees for the 2012 awards.

The competition is being run by the Global Editors Network, supported by Google and in collaboration with the European Journalism Centre.

The University of Auckland’s Jonathan Albright is one of the nominees for his data-driven investigation Did Twitter censor Occupy Wall Street. Congratulations Jonathan!

Winners will be announced on May 31 during the News World Summit in Paris.

See the full list of the fascinating nominees »

I’m very excited to learn that the Data Journalism Handbook is now live and I am looking forward to reading it. The handbook features contributions from over 70 leading practitioners of data journalism from every corner of the globe, from Japan to Finland, Nigeria to the US and from leading news outlets such the New York Times, Zeit Online, the BBC and the Guardian.

It’s an open educational resource, under a creative commons licence (CC-BY-SA) so you may share it and remix it. It is hoped that the handbook will encourage many budding data journalists to look at data as a source and give them courage to tackle it, as well as showcasing some great examples of journalism using data as inspiration for future stories.

You can find the handbook at: http://datajournalismhandbook.org/

Also available for pre-order is the e-book and print version from O’Reilly Media: http://oreil.ly/ddj-e-print.

The Herald has a headline “Scientists call for urgency on cancer-phone link”.  The actual content is ok, but the story does give the impression that it’s scientific consensus vs evil cellphone companies, which is not remotely true.  There’s a more balanced story in the Daily Mail (and that’s not a sentence you want to find yourself writing too often).

The facts:  there has been an increase in frontal lobe and temporal lobe brain tumours in the UK over the past decade, though not in total brain tumours.   If you lump together the two regions of the brain with increases and exclude all the ones with  decreases, you get about a 50% increase in rates, which comes to a bit less than one extra case per 100,000 people per year.   For context, that’s a bit less than the estimates of numbers of deaths due to phone use while driving.    There was a Danish study last year that did not find any differences between cell phone users and non-users, or differences in side of the head for users, but that doesn’t quite contradict the British results, for two reasons.  Firstly, there’s quite a bit of uncertainty in both sets of estimates, and they are just about compatible with, say, a 25% increase.  Secondly, the Danish study was mostly of non-malignant tumours, which are the most common ones, and the British statistics are for malignant tumours, so it’s possible the effect could be different, though there’s no known reason that it should be.

The increase could be chance (it’s statistically significant, but still), or an increase in diagnosis, or be due to something else entirely.  Or it could, perhaps, be due to cellphones.  In order to be confident it is cellphones we’d need much better evidence, especially as there isn’t really a convincing story yet of how cellphones could promote tumour growth.

The obvious textbook example of time trends revealing a cancer cause is smoking and lung cancer: smoking took off during World War I and lung cancer rates followed. Except that really isn’t the story.  When Richard Doll and Austin Bradford Hill set out to do their pioneering case-control study of lung cancer in London they were both smokers.  They were expecting the increases in lung cancer to be something to do with the dramatic increase in cars and bitumen roads — perhaps car exhaust, or perhaps some of the pollutants that evaporate off as roads are laid.  The real explanation was enough of a surprise that they were planning to extend the study to four additional cities as confirmation before publishing (until confirmation came instead from a parallel US study).   In that case the relative risk was 20 rather than 1.5, and the absolute lifetime risk increase was about 15% rather than about 0.05%, so it was a lot easier (and much more important) to find the real cause.

Team Ratings for Week 10

Here are the team ratings prior to Week 10, along with the ratings at the start of the season. I have created a brief description of the method I use for predicting rugby games. Go to my Department home page to see this.

Performance So Far

So far there have been 60 matches played, 41 of which were correctly predicted, a success rate of 68.3%.

Here are the predictions for last week’s games.

Predictions for Week 10

Here are the predictions for Week 10. The prediction is my estimated points difference with a positive margin being a win to the home team, and a negative margin a win to the away team.