Still an awesome chart!

Today the Resolution Foundation released an excellent and fascinating paper looking at data behind Branco Milanovic’s ‘elephant chart’, and asking what conclusions can be realistically drawn from it.

My tweets may have played some small role in popularising the chart – the reporting of an opinion I tweeted that it is ‘the most important of the last decade’ is footnoted a couple of times in the paper, and it even appeared in a Dutch Trade Minister’s speech a couple of weeks ago.

Here’s the tweet, which I drew on my iPad of a picture that I snapped while reading Milanovic’s terrific book:

I have been thrilled to have had a role in drawing attention to the work that Milanovic’s and Lakner have conducted, a summary of which can be read here.

But judging from my Twitter feed this morning you would think that the Resolution Foundation paper has found major methodological flaws that makes a nonsense of the chart.

Not so.

To reiterate, the elephant chart is an amazing chart. It paints in one graphic a picture of the global economy that is (in my opinion) unrivalled. It is so good precisely *because* it combines income changes and demographic changes; it tells the story of recent global history and the degree to which the rise of China (and India) have changed the world. It also illustrates that lower income households in the West have largely not participated in the remarkable global growth over the two decades. The original Milanovic & Lakner paper  dwelt at length on the compositional issues behind the chart, and there was even an animated gif that @MaxCRoser put together using country-specific compositional data contained therein which is pretty stunning, and was widely distributed before inexplicably disappearing from Twitter. Luckily I have been able to find and embed a copy below: global-income

The Resolution report does the world a service by further drawing out the data behind the chart, discussing what policy implications can and cannot be drawn from the chart, and reminding people of the compositional issues.

Compositional issues are hard. And this is probably the most striking chart in the report for people interested in the impact of compositional issues. It even makes its way into the FT.

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This chart is complicated. As its title suggests, it shows ‘Growth in average per capita household income of each percentile group (rolling average) if there had been no income growth and changes were solely due to uneven population growth’.

I think that this means that it imagines a situation where:

  1. every worker is put into an country-specific income decile in 1988, and the mean income of the decile is then fixed in real terms;
  2. net new workers per country are distributed evenly across these country-specific deciles;
  3. all countries for which there is data have their country-specific deciles chucked into a spreadsheet in 2008;
  4. the income required to make it into each percentile in 2008 is then compared to the income required to make it into each percentile in 1988.

The outcome is then charted. (Apologies if I’ve misinterpreted.)

If this understanding is correct, the chart then shows the impact on the elephant chart of

  1. poorer countries having had faster population growth than richer countries;
  2. starting the exercise in 1988 when the global income distribution had the following shape:

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Or, as the author of the Resolution report, Adam Corlett, puts it:

“For example, the poorest decile of people in the US were in the 70-75th percentile range in 1988. But population growth among poorer countries would have pushed those Americans up into the 75th-80th percentile range by 2008. The bottom US decile would be replaced in the 70-75th percentile part of the global distribution by the richest urban Chinese, but the latter’s average income was around $1,500 compared to the former’s $2,600: producing a fall in the average income of those percentiles.”

And so, when holding constant the country population share the elephant chart looks as follows (red line):

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Is this a ‘truer’ version of the original elephant chart? Not at all. In fact, holding constant population shares stable is a nonsense: it no longer shows a picture of profound changes that have been experienced across the global economy as a whole. The author both understands this and makes no attempt to conceal it, because he is trying to do something important and useful to which this new chart is particularly well-suited: to correct a misperception as to what the original elephant chart showed.

Specifically, it issues a corrective to claims that working class developed market incomes have *stagnated* in real terms during the period. And here, despite being one of the people who actually read Milanovic & Lakner, I am at least partly culpable. In a blog for voxeu among other places, I have used the elephant chart and stated “there is a large section of people who are well-off in global terms who have largely not participated in global growth over the past 20 years. That section is populated largely by the Western lower middle and working classes”.  The words may not be technically incorrect, but to say that they fail to draw attention to the compositional issues underlying the chart is more than fair. Furthermore, they mask the fact that while I have looked at US income distribution in some depth, and think myself relatively familiar with the data that is published in the UK, the impact of Japanese income data on the overall chart had passed me by.

When we look at the constant country population share chart from the Resolution paper we can see that my claim that a large section of Western lower middle and working classes largely not participating in global growth might more accurately (but not massively more accurately) be described as having experienced a cumulative real income growth of c25% (although this will vary *meaningfully* by country – with Japanese lower income deciles experiencing contraction, US lower income deciles experiencing low but positive growth, and Western European lower deciles experiencing c45% cumulative income growth). These levels of cumulative income growth have been lower than the income growth at the top of each of the income distributions for the respective developed market block (leading in many developed countries to higher levels of income inequality), and lower than the income growth of the global median or global poor (leading to lower levels of income inequality across the globe, principally due to the rise of China). And so while real incomes have risen for lower middle and working classes in absolute terms, the bottom 80% labour share of GDP in the UK and US has declined as a proportion of GDP (defined as the labour share of GDP multiplied by the proportion of labour income received by the bottom 80% of the income distribution, see chart below), while the relative cost of labour in the West vs the rest of the world has reduced. (It is also notable that the big decline in the UK occurred in the 1980s, with an evening out thereafter.)

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I don’t think that all these things are disconnected, and I’m pretty sure that the Resolution Foundation report isn’t arguing that they are disconnected. Instead, it is seeking to quash a meme that real incomes have stagnated for developed market middle class workers on account of globalisation. It does so with aplomb. As Torsten Bell, also of the Resolution Foundation, blogsboth those saying globalisation automatically benefits everyone and those saying that developed world middle classes have seen no income growth are wrong. Perhaps most crucially, where individual countries lie in between those extreme positions is to a significant degree down to policy choices.”

Given that I read Milanovic & Lakner’s compositional discussions in the original paper, why did I not major on these compositional discussions? Well, I didn’t think that they change the use to which I put the chart (discussing the global labour glut that came about with China joining the global trading system, the associated substitution of capital for labour, and the loss of labour bargaining power in a variety of developed market economies). Although I was not aware of the contribution the Japan had made to the distribution until reading the report.

I tend not to be accused of oversimplifying things. But given the reaction to the Resolution Foundation report, I certainly feel complicit in propagating the end-product of a complex piece of analysis without due caveats.

However, it’s still an awesome chart.

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4 thoughts on “Still an awesome chart!

  1. It’s a rare and beautiful thing on the Internet for someone to a) admit they were wrong and b) explain so clearly why they were wrong. Thank you!

  2. Pingback: Wedge-onomics: Does reading (and writing) finance blogs impair our decision making? - Episode Blog

  3. Pingback: Wedge-onomics: Does reading (and writing) finance blogs impair our decision making? – A view from the desk

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