Today, due to the uneven application of methods and poor availability of data, any ranking of countries by GDP is misleading. The basic problem is that many countries have been using outmoded data and methods. Nigeria’s astonishing upward revision is due to the fact that, until quite recently, the authorities there were still using data and methods from 1990, and have only recently decided to update them. The new methods are capturing a whole range of fresh numbers, such as data from telecommunications (mobile phones) and the service sector. Needless to say, while we wait for the new figures, any comparison between Nigeria’s GDP and another country’s are meaningless.
In research conducted for Poor Numbers I surveyed methods and data in use in national statistical offices in Sub-Saharan Africa. For many countries no official information was obtainable. The IMF Statistics Department periodically reminds authorities to update their baseline statistics every five years (in accordance with international best practice). But within the past seven years, limited resources and data availability have meant that only seven countries (Burundi, Ghana, Malawi, Mauritius, Niger, Rwanda, and Seychelles) were able to follow suit. Of the 34 countries for which information was available, 21 reported having a base year that is within the last decade, while 13 countries have base years from the 1980s and 1990s. This means that our last reasonably accurate picture of these economies is more than a decade old. By comparison, most Western economies update their base years on an annual basis.
Yet the available figures do suggest one likely finding: Many economies in Africa today may be richer than we think. Some of them, like Nigeria, probably are. That’s the good news. The bad news is that we don’t really know for sure. The African growth and income evidence does not tell us as much as we would like to think — and for some countries it’s seriously misleading. It’s disturbing to think that, as recently as last year, we were still working under the assumption that Ghana was a poor country. Now we’ve discovered that we have to re-examine all our ideas.
For both Nigeria and Ghana, the implications are that a large amount of economic activity has gone missing since the 1990s, making it impossible to write the history of those countries based on the official statistics. Were the estimates made in the 1990s exhaustive? When did the economy grow and at what rate? What policies caused the growth?
And we have not even added the informal economic activities within and across countries. And by the way, if you see any figures for those, for obvious reasons, doubt them.
Lee Crawfurd just told me on Twitter that informal activities are captured in household consumption data. That is an excellent point, although the collection of household data – income and consumption – are problematic for different reasons. See section 29 of this UN Economic and Social Council doc on poverty and the informal sector [pdf].