Relative Purchase Power Parity An expansion of the purchase power parity theory suggesting that prices in countries vary for the same product but that they differ by the same proportional rate over time. The reasons suggested for this price difference include taxes, shipping costs and differences in product quality. Investopedia Says: The relative purchase power parity condition suggests that the country with the higher rate of inflation will have a devaluing currency. This is thought to be the case or there will be arbitrage opportunities available. Related Terms: Arbitrage Big Mac PPP Currency Deflation Exchange Rate Inflation Purchasing Power Purchasing Power Parity - PPP |