The article looks at how prices in the U.S. and Mexico compare over time. By analyzing data from 1995 to 2007, the researchers found that the purchasing power parity relationship between the two countries holds in the long run. This means that, on average, the value of goods and services should be similar when converted into a common currency. However, the short-term results were less clear. This study sets the stage for future investigations into how prices in the U.S. and Mexico relate to each other.