The study looked at how the minimum wage in Colombia affected formal and informal sector wages and employment. By analyzing data from an unexpected minimum wage increase in 1999, the researchers found that wages near the minimum wage went up in both sectors, with a larger increase in the formal sector. The wage increases were smaller than expected if employers fully complied with the minimum wage, suggesting partial compliance. Employment in the informal sector decreased slightly, but not in the formal sector. This shows that the minimum wage directly impacts the informal labor market in Colombia.