Deze bronnen zijn afhankelijk van dezelfde basisgegevens, maar modificeren die op verschillende manieren om rekening te kunnen houden met de inflatie en andere factoren.
Jerven mentions three: the World Development Indicators, published by the World Bank (by far the most commonly used dataset); the Penn World Table, released by the University of Pennsylvania; and the Maddison Project at the University of Groningen, which is based on work by the late economist Angus Maddison.