General Schedule Qualification Standards - OPM.gov
Completion of high school or GED diploma. GS-3. Completion of I full academic year of post-high school study. GS-4. Completion of 2 full academic years of post-high school study or an associate's degree. GS-5. Completion of 4 academic years of post-high school leading to a bachelor's degree or equivalent degree. GS-7.