Posts from October 2012 (66)

This week, the  US Bureau of Labor Statistics issued a new jobs estimate that was more favorable than the previous one: good economic news, for a change.

Since the US is in an election campaign (as it is about half the time), a few conspiracy theorists came up with the idea that the new jobs weren’t real, but were part of a plot to re-elect the President.  The theory comes in two flavours: either that unemployed Democrats all over the country lied about having part time jobs in order to improve Obama’s position, or that the Bureau of Labor Statistics faked the numbers.

The idea that millions of people have just now, for the first time, decided simultaneously to pretend to have jobs collapses under its own weight. The idea of an official statistics conspiracy makes sense only if you don’t know anything about the Bureau of Labor Statistics.

Well-run official statistics agencies, such as the US and Canadian ones (and Stats NZ) are set up to make it hard for the current government to fudge the figures.  Even for something much less important than the employment figures, attempts by the White House to change the results would, at the minimum, result in senior public servants deciding to spend more time with their families or explore exciting new employment opportunities outside the government sector.  (see, for example, the Canadian census debacle)

The employment figures are guarded much more carefully, because of their impacts on politics, economics, and the financial markets.  If the Democrats, who are already ahead in the polls,  were going to risk a scandal that would dwarf Watergate, they’d want to get more out of it than three tenths of a percentage point in the unemployment rate, about 1.5 times the margin of error.

Two more colour links for your weekend:

• the XKCD colour survey has colour names based on more than 200,000 user sessions and five million submitted names. (this is barney purple and this is mahogany)
• Crowdflower has a multilingual version, though with a much smaller sample size (via)

There are lots of resources for colour choice out there, my favorite being ColorBrewer .

Here’s an interesting article about algorithms for choosing sets of colours, for when you want clear and attractive colours, but you don’t want the same ones each time. (via)

This just in from the BBC:

Could it be that Labour leader Ed Miliband’s demand that all school pupils must study maths until they are 18 has been prompted by new evidence that his own MPs struggle with numbers?

The man in charge of the party’s policy review, Jon Cruddas, admitted this weekend that he is “barely numerate”. And when the Royal Statistical Society (RSS) recently tested the ability of honourable members to answer a relatively simple mathematical question, only a quarter of Labour MPs got it right.

Read the rest of the yarn here.

One of my favorite ambiguously-hyphenated phrases, but in this example the hyphen definitely goes after the second word.

The Herald tells us (or reprints the Daily Mail telling us):

Children who eat junk food will grow up to have a lower IQ than those who regularly eat fresh, home-cooked cooked meals, a study reveals.

Childhood nutrition has long lasting effects on IQ, even after previous intelligence and wealth and social status are taken into account, according to the paper.

 You’d think from that description that the study looked at children growing up, and that they found effects of meals in the past rather than the present. And that the effects were big.  None of these is the case.

The paper (paywalled) looked at cognitive function tests and meals at ages 3 and 5 for a group of children.  The analysis found that 5-year IQ was related to meals at age 5, but not (or more weakly) to meals at age 3, and, to quote the researchers themselves

 Overall, having more often slow meals accounted for negligible amounts of variance in cognitive change.

where `negligible’ means less than 1%.

You’d also worry about other differences between families that might be associated with IQ-test performance.  The quote tells us that previous intelligence and wealth and social status were taken into account, but the ‘wealth and social status’ in the statistical models was just a single five-point scale, and there’s no way that could reliably account for socio-economic differences.

Matthew Yglesias, who writes a generally sensible and data-heavy opinion column at Slate, has been arguing (correctly) that US immigration policy deserves much more attention than it gets:

Things that save lives often cost money, and governments and individuals around the world need to decide how much they are willing to give up in order to save one life or prevent one serious injury.  These decisions imply some value for a death prevented, and under some moderately unrealistic assumptions about how people think, you could argue that the implied values should be consistent for different decisions, giving us social costs of various policy issues.

But if you are going to say, as Stuff quotes Godfrey Bridger saying

“There’s also the enormous saving in human suffering and misery which isn’t captured in these statistics. A national road lighting upgrade is a no-brainer.”

you can’t also quote costs that do ‘capture the human suffering and misery’, such as

the estimated $1.2 billion annual cost of night-time road deaths and injuries.

The estimated $1.2 billion annual cost is for 61 deaths and 1538 injuries on the roads at night.  It’s immediately obvious that these can’t be actual cash costs — nearly a million dollars per injury — so they must include some sort of value of a life.  It’s less clear whether they also include physical and emotional pain from injuries, but if they don’t, the estimated value of a life lost must be very high.  This is one the journalists should have caught: the basic journalism rule for numbers is “if you have two numbers, do something with them”. In this case, divide them.

You can either separate out monetary and non-monetary costs, on the grounds that different people weigh them differently, or combine them, on the grounds that government spending should treat all lives the same, but you can’t have it both ways.

….but why?

The Herald passes on figures from a

New Zealand is overweight – collectively the adult population weighs more than 232,000 tonnes.

But while New Zealand accounts for only 0.08 per cent of the total weight of the world adult population, it makes up 0.22 per cent of the world’s excess weight due to obesity, according to a new study.

It makes sense to talk about NZ having more than its share of carbon emissions, because this is a global resource that is valuable to everyone.  Obesity, not so much. Alternatively, it could make sense if there was a linearly increasing health risk with weight, but again there isn’t: there’s a broad low-risk region with health risks increasing dramatically at higher or lower levels.

Mind the Science Gap is a blog from the University of Michigan:

Each semester, ten Master of Public Health students from the University of Michigan participate in a course on Communicating Science through Social Media. Each student on the course is required to post weekly articles here as they learn how to translate complex science into something a broad audience can understand and appreciate. And in doing so they are evaluated in the most brutal way possible – by you: the audience they are writing for!

The post that attracted me to the blog was on sugar and hyperactivity in kids, not just for the science, but because someone has actually found a good use for animated GIFs in communicating information: click to see the effect, since embedding it in WordPress seems to kill it.

Citizen Statistician is a new blog from Rob Gould and others at the Department of Statistics, UCLA. The blog discusses statistics in the age of the “Data Deluge”, an age in which data are large, complex, everywhere visible, accessible, and where data analysis tools are available to everyone.

To date, they’ve been discussing how to get personal Fit Bit data and Yelp data.

We’ve also added the blog to our list of recommended sites down the sidebar of Stats Chat.