When the first World Trade Center attacks happened, a major overhaul commenced for Immigration and Naturalization Services. This overhaul was ready to take affect nearly a decade later when the INS was split in two by the new Homeland Security Department. Cohen discusses some key differences in the agency before and after the split. She also includes a detailed explanation of what the new system looks like and how it works. Another useful portion of the tipsheet has charts that describe different places to get immigration data, what the data includes, and any problems inherent in the data.