The article explores how excluding certain types of businesses from investment portfolios affects returns and risks. By analyzing data from various markets over 10 years, the researchers found that the impact of exclusions on returns and risks varies depending on the region and type of exclusion. They discovered that the relationship between exclusions and returns is not consistent, and the direction of this impact differs across regions. Factors like style factor exposures also play a role in determining returns. Ultimately, the study suggests that investors should carefully consider which exclusions to make in their portfolios and how these exclusions may affect their investment strategies.