Morten Jerven Morten Jerven

A history of economic growth in Africa: why measurement matters

The GDP re-basing in Nigeria again brought measurement to the center of debates on African economic development, just like it happened when Ghana re-based their GDP in 2010.

There has been more commentary in mainstream media this time around – and also a fair bit of confusion. Like in Joshua Keating the Slate Magazine stating that:

Nigeria hadn’t calculated its GDP since 1990

Not quite. The real issue is rather that we have different calculations now. Izabella Kaminska in the Financial Times get closer, when she says that:

To come up with a growth rate, statisticians compare one snapshot of the economy with another. They do this by looking at what’s spent in the economy in two different periods.

Closer. As I show in a previous post here, the issue is that we got two different pictures for the same year of the Nigerian economy. That is completely normal by the way – and you could generate many more given available data, different definitions, weights and so forth.

This is all carefully explained in Poor Numbers, and for those who want detail they should really consider consulting my second book Economic Growth and Measurement Reconsidered in Botswana, Kenya, Tanzania, and Zambia, 1965-1995

The key question is not only how the ‘new’ number affects rankings and which is the biggest economy and so fort. For scholars the key questions would be how these changes of measurement make us rethink how we evaluate growth performances.

I have written a post about this for the Royal Statistical Society – read all about it here.


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