The FAFSA has replaced what has been previously known as the EFC (Estimated Family Contribution). Now, EFC is SAI, which stands for Student Aid Index.
The SAI is a different way to determine aid eligibility, and schools will also be using the SAI to determine eligibility for federal aid programs.
In previous years, the EFC calculation included the number of family members in college. With the SAI now taking over, it will not include the number of family members in college, which may reduce the need-based aid for students whose siblings are also in college.