Bilateral Investment Treaties (BITs) are agreements between countries to boost foreign investment. A study looked at how BITs affect investment flows from rich to poor countries. The results show that the impact of BITs on investment varies depending on the economic and institutional differences between the countries involved. BITs tend to increase investment when there is a big gap in GDP and GDP per capita between the countries. However, BITs don't seem to make a difference when the countries have very different political systems.