Should PPP GDP Per Capita Data Be Used With or Without Reservation?

This paper analyzes the differences between real gross domestic product (GDP) per capita data using purchasing power parity (PPP) with World Development Indicators (WDI) and the Penn World Table (PWT). While these indicators are frequently used by researchers and the mass media, the differences between them have not been thoroughly investigated. The conclusion of this paper is that, while the WDI data is generally slightly higher than those of the PWT, the rank order between these indicators is consistent. However, both the income levels and the rankings of income of certain countries differ markedly between these two data sets. It is therefore necessary to employ caution when using PPP GDP data for a particular country