The study looked at how business cycles in different countries are connected. They used data from 187 countries between 1960 and 2007. They found that business cycles in countries are influenced by how close they are geographically. This effect was strongest during international shocks from 1973 to 1986, but became less important during globalization from 1987 to 2007. However, trade relations between countries still play a significant role in how their business cycles move together during the globalization era.