Posts filed under Just look it up (285)

From the Herald

Log exports to China are driving an increase in the value of New Zealand’s forestry products – which has more than doubled in the past 20 years, according to figures from Statistics New Zealand.

and from Stats NZ, this infographic (click to embiggen, as usual)

In both the infographic and the Herald story there’s interesting information about changes in the makeup of NZ forestry exports (more logs, more to China), but in both cases the headline number is a bit misleading.

The change is from $1.9 billion in 1992 dollars to $4.5 billion in 2012 dollars. It’s not explicit that the dollar values are nominal, but they are — if I were a newspaper I’d say “evidence obtained by StatsChat under the Official Information Act”, which is to say I asked the always-helpful @StatisticsNZ twitter account.

My general view is that comparing nominal dollars twenty years apart is Not Even Wrong, but I have to admit it’s not obvious what the ideal adjustment would be. Consumer Price Index? Producer Price Index? Something that involves exchange rates? For that reason, here’s a selection of adjustments

• CPI: $1.9 billion in 1992 is $2.97 billion now, using the Reserve Bank’s calculator, which all journalists should have bookmarked
• PPI (outputs, all industries) $1.9b in 1992 is $3 billion now
• PPI (inputs, all industries) $1.9b in 1992 is $3.1 billion now
• As a proportion of GDP, forestry has fallen from 2.5% to 2.1%
• As a proportion of all exports, forestry has fallen from 10.4% to 9.4%

So, there’s a reasonable degree of agreement between measures that forestry has increased in value about 50% and has fallen slightly as a fraction of the economy. “More than doubled” doesn’t seem defensible.

(via @kiwieric)

Both Stuff and the Herald have stories today based on MFAT statistics on consular assistance provided for deaths and accidents overseas.  The basic message is that deaths overseas are increasing.

Both sites have interactive graphics: Stuff has a clicky map, and the Herald has barplots where you can select a country. A very nice feature of the Herald story is that they have more data, and a link to let you download it. They got the data under the Official Information Act, which is an impressive-sounding way of saying they asked MFAT for it (as Graeme Edgeler has pointed out, even ringing up some departmental office and asking what time they’re open is an Official Information Act request.)

From the extended data it’s clear that consular assistance for deaths is up a lot over time. That’s a much bigger increase than the number of trips overseas, and the increase looks pretty similar if you exclude Australia, which is unrepresentative because so many Kiwis actually live there. I don’t have any real idea why this is happening, and apparently neither do the journalists.

It’s interesting to look at how dangerous foreign travel is based on these data.  For Thailand, the story in Stuff quotes 115000 trips and 18 deaths in the 9 months to September 2013. That gives a mortality rate of 0.16 per 1000 trips. The annual mortality rate for New Zealand as a whole is 6.8 per 1000 people per year, but travellers tend to be younger and healthier than average. For twentysomethings, the annual mortality rate is about 0.6 per 1000 per year, so the average trip uses up at most 3 months worth of mortality risk — travelling to Thailand is dangerous, but not very dangerous.   Even then, we can’t be sure that it’s Thailand that is dangerous: other contributing explanations could be that people do riskier things while they are there, or that the sort of people who travel to Thailand are prone to taking more risks.  The figure for all countries is about half that for Thailand, though it’s less reliable because of the difficulty in knowing how to handle Australia.

The figures for deaths while travelling should be fairly reliable — I’d expect most deaths of travellers to require some consular assistance — but the figures for accidents are obviously less complete. That didn’t stop Stuff saying

But according to the figures, deaths far outnumber accidents and injuries for New Zealanders across the globe.

The phrase “according to the figures” is doing a lot of work in that sentence, if you want to be able to say it with a straight face.

Update: Luis Apiolaza tracked down data(XLS) on deaths of visitors to NZ. Mortality is about 0.05-0.07 per 1000 trips. Visitors are safer here than we are abroad.

It’s cold in the United States at the moment. Very cold. Temperatures in places where lots of people live are down below -20C (before worrying about the wind chill).This isn’t just hypothermia weather, this is ‘exposed skin freezes in minutes’ weather, and hasn’t been seen on such a large scale for decades. So why isn’t this evidence against global warming?

It will be a month or two before we have the global data, but the severe cold snaps in recent years have been due to cold air being in unusual places, rather than to the world being colder that week. For example, November 2013 was also cold in the North America, but it was warm in northern Russia; the cold had just moved (map from NASA).

The cold spells in Europe in recent years have been matched by warm spells in Greenland and northeast Canada. You don’t hear about these as much, because hardly anyone lives there.  The ‘polar vortex‘ being described on the US news is an example of the same thing: cold air that usually stays near the pole has moved down to places where people live. That suggests the global temperature anomaly maps for December/January will show warmer-than-usual conditions in other parts of the far northern hemisphere.

For contrast, look at the heat wave in Australia last January, when the Bureau of Meteorology had to find a new colour to depict really, really, really hot. This map is from the same NASA source (just a different projection)

Not only was all of Australia hot, the ocean south of Australia was warmer than typical. This wasn’t a case of cold air from the Southern Ocean failing to reach Australia, which causes heat waves in Melbourne several times a year. It doesn’t look like a case of just moving heat around.

No single weather event can provide any meaningful evidence for or against global warming. What’s important for honest scientific lobbying is whether this sort of event is likely to become more common as a result. The Australian heat waves definitely are. The situation is less clear for the US winter cold: the baseline temperatures will go up, which will mitigate future cold snaps, but there is some initial theoretical support for the idea that warming of the Arctic Ocean increases the likelihood that polar vortices will wander off into inhabited areas.

[note: you can also see in the Jan 2013 picture that the warm winter in the US was partly balanced by cold in Siberia that you didn’t hear so much about]

From Cameron Beccario, an interactive visualisation of wind speeds around the world, with your choice of projection, and winds at levels from ground up to the stratosphere.

This is a satellite photo of the 5th most densely populated census area unit (out of 411) in the Auckland supercity, based on 2013 census data.

(more…)

Nick Iversen nominated the Herald’s story on increasing inequality as Stat of the Week, on the grounds that it didn’t have any data showing increasing inequality. That’s slightly unfair — the increase in high incomes is not explainable by inflation — but it’s certainly true that the conclusion was pretty weakly supported by the numbers.

Firstly, any comparison of money in 2006 to money in 2013 that’s not inflation-adjusted in some way is pretty pointless. The CPI went up 19% over that period.

Secondly, minimum wages are pretty obviously relevant. At the last Census, the minimum wage was $9.50; at this Census it was $13.50, a nominal increase of 42% and a real increase of  19%.

Thirdly, there are established ways to measure income inequality, and while they aren’t perfect, they are better than trying to reinvent the wheel.  From an Inequality Forum earlier this year,  we can find some summaries based on survey data (PDF) of the ratio of the 80th to 20th percentile of income, and the Gini index.  Here’s the 80:20 ratio, with the blue line for income before subtracting housing costs and the red line for income after subtracting housing costs. Both have gone down since 2006, though up since the 1980s, and housing costs are clearly a fair chunk of the inequality problem.

The Gini index is a more complicated summary of inequality that uses all the data, not just two percentiles. It’s popular for comparing between times and between countries.  The Gini index for raw income (before taxes and benefits) has stayed fairly stable in NZ recently.

The Gini index for income after taxes and benefits will have increased, but probably not by a lot.

So, inequality in NZ is substantially higher than it used to be, and there are a lot of reasons to think this is bad, but the increase was in the 1980s and 1990s, not since 2006.  And this information is not hard to find.

• The Herald has a nice display of how the percentage of first-home buyers varies across Auckland. I think (though the text could be clearer) that this is data since the start of 2012. I don’t know exactly how they define first-home buyers: quite a few immigrants, like me, will have been home owners outside NZ before buying a home here.
• From wtfiz.net, originally a section of an infographic from graphs.net 

To start with, the noseless guy doesn’t cast a shadow, although the almighty dollar he is holding casts a shadow on the empty air. Perhaps he’s a vampire. Also, the colours in the legend don’t actually match the colours in the graph. And, the graph manages to misrepresent not only the magnitude of the numbers but even their ordering, with the largest layer of the pyramid representing the smallest category.  To top it all off, the numbers aren’t even right (or are seriously outdated) — for example, the US Bureau of Labor Statistics Consumer Expenditure Survey reports food expenditure between 12.5% and 13% of  household expenditure every year from 2006 to 2012, not the 15% in the graph

The detailed Ministry of Transport paper on changing the legal blood alcohol limit is now available.  There’s a story in Stuff, which is, if anything, unduly critical (an interesting change). It doesn’t mention the cost-benefit analysis, and implies a fines grab

Transport officials calculate nearly 20,000 people will be caught by the lower drink-driving limit – earning the Government $5 million extra in fines. 

which is a bit misleading since the report (paragraph 93) actually estimates a net increase in costs to the justice system of about $2 million in the first year and about half a million in subsequent years, ie, the fines don’t cover the costs of enforcing the change.

Basically, whether the change is a benefit or not depends on how much inconvenience and risk is caused to the average driver, the only major component that isn’t taken into account in the calculations.  If this is worth only 50c/month or so, the policy makes sense. If it’s worth a few dollars a month, not.

On the other hand, the policy is popular, and since most people should have a reasonable appreciation for how the change will affect them personally, that’s a more persuasive argument than it would ordinarily be.

The members of the Organisation for Economic Cooperation and Development (OECD) are a popular reference set when comparing NZ performance.  Or at least, they used to be. The OECD has expanded over the decades since it was formed, and not everyone’s referencing has kept up.

Yesterday, I wrote about imprisonment rates. Today, a (mostly good) Dominion Post editorial about sex education said

New Zealand has the third highest teen pregnancy rate among OECD countries.

In fact, the OECD said last year (their most recent report, PDF) that NZ has the ninth highest teen pregnancy rate among OECD countries:

It is third-highest among countries that joined the OECD before 1990, but that’s starting to look less like a natural comparison.

The other point the graph makes is that teenage pregnancy is less common than it used to be, essentially everywhere where there is data. The editorial argues that the internet has made alternatives to proper sex education worse than they used to be.  That’s a reasonable position on some important issues, but it clearly doesn’t apply to teen pregnancy, and it would be nice to see this admitted more often.

From Stuff

New Zealand had the second highest imprisonment rate in the world, with an overrepresentation and disproportionate rate of Maori prisoners. “This has attracted comment from the United Nations and overseas media.”

This is half right. There is certainly serious overrepresentation of Maori in the prison population. However, New Zealand doesn’t have the second highest imprisonment rate in the world. Or even in the OECD. And it’s not hard to find this out.

The Encyclopedia of New Zealand, Te Ara,  gives this graph, dated May 2011, for OECD countries, referencing the International Center for Prison Studies (PDF)

Wikipedia has NZ in 74th place for all countries, referencing the same source, behind most of the Caribbean, much of the former Eastern Bloc, and Samoa. So, whether you’re going for easily accessible online references like Wikipedia and Te Ara or actual expert data curation, you get the same results.

New Zealand’s imprisonment rate is too high. I don’t see a good reason why it should be much higher than, say, Australia or the less wealthy Western European countries. But it’s not second in the world by any reasonable definition of “the world”.

(Update: Graeme Edgeler wrote about another airing of this recently, which I had thought I remembered, but couldn’t find when writing this.)