2604.01199 Purchasing Power Parity Estimates Shift Country Rankings by Up to 15 Positions with Base-Year Choice: A Bootstrap Audit of World Bank ICP Rounds
Purchasing Power Parity (PPP) conversion factors from the International Comparison Program (ICP) underpin virtually all cross-country income comparisons, yet each ICP round selects a different base year and product basket, introducing systematic sensitivity into the resulting real GDP estimates. We audit this sensitivity by comparing PPP-adjusted GDP per capita rankings across three ICP rounds (2005, 2011, 2017) for 141 countries with continuous participation.