What went wrong and how?
Statistical adjustment in charts

Lost in complexity

Felix Salmon (link) and others linked to this BBC News graphic about European debt recently.



At first sight, the use of arrows inside a ring, enhanced by an interactive filter by country, seems to be an inspired idea.

Then, I started clicking. Here is the German view.


According to the paragraph beneath the headline, the arrows show how much money is owed by each country to banks in other nations. So, it appears that German banks have lentborrowed about equal amounts tofrom France and Italy, and also good amounts tofrom the U.S., the U.K. and Japan. And German banks would be affected if these debtors were to default.

Now, take a look at the right column where BBC tells us "The biggest European economy is exposed to Greek, Irish and Portuguese, but mostly, Spanish debt." Say what?

Much more important than appearance, the designer must ensure that the data and conclusions make sense. Here, the chart doesn't support the discussion.


See also my previous post about Europe debt. 




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The arrows show money owed, not lent.


RTFM: "The arrows point from the debtor to the creditor"


at first sign it looks like Europe and US. But they have Japan as well but not China. US owns lot more to China yet it isn't mentioned. I fail to understand how this list of countries was generated.


NR, Bob: Fixed the direction of lending. My general point still stands, which is that the chart doesn't support the discussion.


It also doesn't explain very well what the indebtedness actually is. It says the numbers are amounts "owed by each country to banks in other countries." I understand who the creditors are (banks), but what does it mean to say a "country" owes them?

So if you look at the numbers, Germany owes 207Bn to Italy but it's only 120Bn in reverse. German and Italian foreign debts are fairly close as a % of GDP. And Germany has much higher debt per person than Italy.

So this does very little to explain current events at all.


The software to generate this graphic looks like Circos. It is a genomics visualisation tool that business journalists seem to quite like too.

I've used it a bit (I work in genomics), it's rather powerful but takes someone not shy of a command line and a bit of coding to set up.


@ MySchizoBuddy:
the connection china - US is irrelevant for a chart called "eurozone debt"



The Japan - US connection isn't Eurozone debt either.

Does the Eurozone not have a meaningful debt relationship with China?


I saw this on the BBC webiste and was amazed by the figures listed :-o


As a member of the team that created the above graphic, I thought I'd attempt to respond to some of the criticisms. Apologies if it's a little on the long side...

So, the debt web attempts to show, as explained beneath the graphic, what banks in one country are owed by debtors - both government and private - in another country. As some of you have already pointed out, the arrows point from the debtor to the creditor, not the other way around.

However, I take your point about starting the text with Germany's exposure, rather than its indebtedness. This was mainly because the thrust of the news coverage at the time was about exposure risk. We've now changed the text around to, hopefully, make this clearer.

On the other point made about the choice of countries (explained beneath the graphic and in the FAQs linked from it) - the US and Japanese economies were chosen for their size and their unique positions in terms of debt. The US being highly in debt, but still seen as a safe bet, and Japan having a large amount of public debt, but owing this mostly internally. China would have been included too, however comparable data was not available. We note this too under the graphic and explain further in the FAQs linked beneath.

We also felt it was important to show key countries outside the eurozone because of the discussion at the time of "contagion" - fears that a collapse of the eurozone would lead to infection outside it. The introduction to the graphic makes it clear that it features "some of the main players in the eurozone as well as other big world economies".

We added a feedback form at the time the graphic was published, and most responders (in particular people who had never engaged in the subject) found it easy to navigate and understand. Hopefully the tweaks we've made will now make it more so. Some other answers to some of the most frequently-asked questions are linked from beneath the graphic if you're interested.


Lucy: Thanks for taking the time to talk to us here. I actually quite like the arrow and circle format. I'm glad to see you aligned the text and the chart. This debt data is difficult to work with because debt goes in both directions. I wonder if there is a way - in the case of Germany - for the chart to show both who they owe and who they lend to.

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