Ok, pop quiz: What’s the world’s largest economy, as defined by GDP?
The answer is “it depends on who you ask.”* If you want internationally comparable GDP data, there are three main places to look: The Penn World Tables, The World Bank, and Angus Maddison’s database. According to inequality researcher Branko Milanovic, right now, the last database puts China in the lead, while the first two give it to the US. New revisions of the Penn tables put them closer to the US, but not all the way there. But the Penn World Tables are constantly in flux, and Milanovic predicts that the next round of revisions might put China in the lead. Here’s how he put it, in confusing reverse order because Twitter:
The range of the three is quite large: from China being 10% higher than the US to 25% lower. As Morten Jerven has shown, this problem (of large variation between the different data sets) is pervasive, and especially problematic for African countries.
* It also depends on *how* you ask (which PPP data you use, etc.), which amounts to something very similar.