*Note: The country is only getting richer on paper, but that change may make a difference in the real world.* People talk about GDP as if it means something solid, as if it’s a mathematically derived and agreed upon fact. But in conversations we’ve had in the last few weeks, we’ve become more convinced that GDP is a wobbly fact. It’s malleable, and it’s mushy. GDP can change in a day. And when it does — even when it’s a statistical illusion — that illusion can still have a major impact on millions of lives. On today’s show, Nigeria is about to change the way it calculates its GDP. The change will likely make Nigeria the leading economy in Africa, and it could be a big boost for the Nigerian entrepreneurs behind Pledge 51, a mobile app company based in Lagos. The guys behind Pledge 51 have found success with mobile apps like Danfo, a game which lets players pretend to drive the notoriously wild buses in Lagos. But to take their company to the next level, they want foreign investment. A boost to their country’s GDP could bring in exactly the type of foreign investors they are hoping for. Correction: A previous version of this show incorrectly stated that the World Bank lends out $35 million a year. The correct number is $35 billion.