Posts from July 2013 (70)

In yesterday’s coronation lifetables post, it turned out that a 39-yr old UK male had about a 32% chance of outliving a 31-yr old UK male.  That’s because there is quite a lot of variation around the mean life expectancy.

One might try estimating Ben Goldacre’s chance of seeing King George by working out Prince William’s life expectancy and then seeing how likely Ben is to be alive at that expected date.  The calculation ignores the uncertainty in Prince William’s lifespan, and it ends up with a serious underestimate of 20%.   If Ben Goldacre is still alive at baby George’s coronation, it is could well be because the coronation happens earlier than expected, and just using the mean life expectancy ignores this possibility.

The same issue arises in some of the tweets reacting to the StatsChat post, eg from James Shield “For me, about 70%, which seems high. My guess is I’ll be 86.”  The 70% probability is so high precisely because the event could happen before he is 86.

Two selections from radicalcartography (via Noah Illinsky on Twitter)

The Mercator projection (and other projections) with copies of the US superimposed for reference

(the Mercator projection has the unique property, vital for pre-modern navigation, that compass bearings are straight lines.  It shouldn’t be used where this property isn’t needed).

And social survey data on how people greet friends in France

(as the cartographer notes, the data come from a bogus poll and may be somewhat unreliable)

Ben Goldacre asked on Twitter

I’m 39, Prince William is 31, what are the odds of me seeing King George on the throne? Taking current projected mortality trends, that is.

— ben goldacre (@bengoldacre) July 24, 2013

As he suggests, we’re going to have to make some oversimplifications.  Both Prince William (who comes from a wealthy, long-lived family) and Ben Goldacre (who is a skinny, hyperactive medical doctor) are likely to live longer than the typical UK male, and we will ignore this.  We will also ignore the possibilities that Baby George dies before his father, or that William dies before his father or grandmother, and the possibility that there won’t be a throne for King George.

Now we need to get life tables for UK males, which give the current risk of death at each age.  For each year into the future, we multiply the chance of Prince William dying in that year by the chance that Dr Goldacre is still alive, and add these up, to get a little over 30%

We can do the same thing for UK females and (with NZ life tables) for NZ males and females

According to The Conversation, that’s the name of a group petitioning Queensland radio station Triple J to include at least 20 seconds of science news in their news updates.  They’ve got support from one of the great science journalists, Robyn Williams, and from an ANU survey that found science news was regarded as more interesting than politics or sports news

Team Ratings for Round 20

Here are the team ratings prior to Round 20, 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 136 matches played, 84 of which were correctly predicted, a success rate of 61.76%.

Here are the predictions for last week’s games.

Predictions for Round 20

Here are the predictions for Round 20. 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

This year the predictions have been slightly changed with the help of a student, Joshua Dale. The home ground advantage now is different when both teams are from the same country to when the teams are from different countries. 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 122 matches played, 85 of which were correctly predicted, a success rate of 69.7%.

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.

• Some 1920-30s cartograms (distorted maps) of the USA, at Making Maps. Here’s the one based on electricity use
  
• Another map: the USA has low income mobility (ie, children of the poor stay poor), but there is quite a lot of variation over the country. This is the version of the map from the original researchers, click for the shiny interactive New York Times version
  
• A good story about a new randomized trial of a melanoma vaccine, based on NZ research.  The story even says that the trial is measuring specific components of immune response, not (yet) actual disease.  As should always be the case, the trial is registered and there’s more detail at the registry.
• A post about wild extrapolation in estimating the value of marine reserves to (UK) anglers:
  Or you could look at the Celtic Deep rMPA, a site located some 70km offshore, where they estimate between 145,000 and 263,000 angling visits per year. That’s 400-720 visits a day, which translates to approx 40-70 typical sea angling boats, each full to the gunwales every single day of the year.

Today, for example, I found out what these ads in bus stops were for

Sovereign, the insurance company, has a survey of ‘wellbeing’, and wants you to participate.

The survey that produced the numbers in the ad is reasonably real research — it’s based on a random sample from an online survey panel — but

Would you like to be included in the next Sovereign Wellbeing Index results? If so take the full survey here.

together with the links on the ads suggests that they are going to augment the real survey with a bogus poll.

The survey results are interesting. They find that NZ has lower reported wellbeing than most other countries.  It’s not clear why this should be the case (and it disagrees with some other surveys), but one cynical suggestion is that a certain subset of Kiwis may have unintended reactions to questions like

I actively contribute to the happiness and wellbeing of others

From Scoop, in a press release on the legal-highs bill by Manurewa Local Board member Toa Greening

Ireland led the way by prohibiting all non-prescribed psychoactive substances back in 2010. This resulted in an immediate reduction in related psychoactive substance health issues and crime.

Irish data on recorded crimes is available throught the Ireland Official Statistics portal, Statcentral.ie.  This graph shows quarterly data since 2004 for the main crime categories (the heavy blue line is drug offenses, and the vertical line is when the ban came into force)

I don’t see any dramatic effects of the ban on any category of crime.

The Herald has a story about high rates of depression in young Australian men, which gives very little information about what the data was like and where it came from.  Often that’s a sign that the people who came up with the numbers would really prefer you not know how they did it.

In this case, though, the research is from a well-designed  survey with computer-based interviewing of people chosen by dialling random telephone numbers, and there’s a detailed description of the research program and a glossy but carefully-written and informative report (PDF) available.