Calculate this country’s GDP

national accountsLast week, the media reported on the questions Oxford University asked candidates as part of their entrance interview. The questions aren’t designed to test knowledge of facts, but to give students a chance to show how they think about solving problems, whether they can see links between one subject taught at school and another, and so on. One of the questions in history was “How much of the past can you count?”. The idea, as interviewer Stephen Tuck told the Daily Mail, is to provoke a discussion about “all sorts of issues relating to historical evidence. For which periods and places and aspects of the past is data readily available?”. It’s a question you could ask in economics too: how much of a country can you count? And one that the newly updated Understanding National Accounts from the OECD answers.

Governments have always wanted to have data on who and what they govern – a population census is part of the Christmas story for instance – and, as we mentioned in this post, the origins of the modern system of counting a country can be traced back to the 17th century and William Petty’s Political Arithmetick. Petty developed and applied his techniques in England’s first colony, surveying land in Ireland that was to be given to Oliver Cromwell’s troops. His statistical methods were rudimentary, often involving estimation based on exports, deaths and the number 30: a 30% increase in exports means the population increased by 30%; multiply the number of deaths by 30 to find out the size of the population. His components of national accounts though contain much that is still familiar – land, real estate and other personal property, ships…

How though do you count all this? Samuel Beckett, one of the Anglo-Irish descendants of Cromwell’s invaders, tackles this problem in Malone Dies, when the eponymous hero decides, on his deathbed, to make a list of everything he possesses. He’s overwhelmed by the complexity of the task and can’t figure out what to include and how. (Is a pair of shoes one or two items? And what about the laces?). In fact he doesn’t get much further than the pencil and notebook he was going to use to make his inventory and gives up.

OECD statisticians are made of sterner stuff, and know exactly what they’re including and why. Petty would recognise our colleagues’ claim to provide “information on the economic interactions taking place between different sectors of the economy (households, corporations, government, non-profit institutions and the rest of the world) to allow for macroeconomic analysis and evidence-based decision making”.

Given the military origins of his Arithmetick, he’d also be pleased to see the main change in the new system of calculations introduced in 2008: “…expenditure on research and development and weapons systems (warships, submarines, military aircraft, tanks, etc.) are now included in gross fixed capital formation, i.e. investment. This is recognition that expenditure on these items provides long-lasting services to businesses, non-profit institutions, and the governments who use them. This increases the level of GDP across time, but the impact on GDP growth rates will generally be minor.”

Understanding National Accounts was first published in 2006 to give experts and non-experts a practical summary of how to calculate the accounts, but also an understanding of the principles and data sources behind them. Most countries have now adopted the 2008 methodology, but the new edition reflects three other developments too.

First, the financial crisis highlighted the need to better explain how strong movements in economic activity are actually reflected in national accounts. Second, national accounts can be a source for tracking households’ material well-being in line with the emphasis on “better lives”, beyond the traditional objective of economic growth and GDP, exemplified by the OECD Better Lives Initiative,. Finally, the data on trade in value added now being compiled in parallel to core national accounts shed a new light on the interconnectedness of economies.

Obviously somebody reading about national accounts already has some interest in economics, but one of the strengths of the book is that it takes nothing for granted, and explains every technical term clearly and simply, even familiar ones like “the bizarre title “Gross Domestic Product”, or GDP”. Likewise, to explain the difference between GDP and gross national income (GNI), it uses a simple example: “The earnings of workers living in Germany but working in neighbouring parts of Switzerland or Luxembourg have to be added to the German GDP to obtain its GNI. Conversely, the earnings of the seasonal or regular workers living in France or Poland and working across the border in Germany have to be deducted from the German GDP to obtain the German GNI.”

Once you’ve read the main text, you can test your knowledge using a series of exercises (the answers are provided). It’s true that “Calculate the GDP of this economy” is for the bold and the brave, but maybe all national accountants recognise themselves in Petty’s birth horoscope: “Jupiter in Cancer makes him fat at heart”, even if they’d prefer to avoid a second opinion that “vomits would be excellent good for him”.

Useful links

OECD Statistics Directorate

OECD data portal

Is GDP a satisfactory measure of growth? François Lequiller, co-author of Understanding National Accounts talks to the OECD Observer

Patrick Love

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