From USAJOBS Help
The following are general rules:
- One can qualify for jobs at the GS-2 level with a high school diploma or as little as 3-months of general work experience. At GS-3 and GS-4 grade levels, more months of general experience is required. Starting at the GS-5 grade level, jobs generally require 1 year of specialized experience to qualify which may include specific job-related work experience, education, medical or physical standards, training, security, and/or licensure.
- A degree but no specialized experience in a career field, makes one eligible for appointment at the GS-5 grade level. If you maintained at least a B average; were in the upper third of your college, university or major subdivision; or are a member of a national scholastic honor society recognized by the Association of College Honors Societies, you can start out at the GS-7 grade level.)
- To qualify for jobs at the GS-7 and higher grade levels, background must include experience closely related to the work to be performed in the job for which you are applying.
- One can qualify for GS-9 positions on the basis of a masterâ€™s degree, and for GS-11 positions on the basis of a doctorate.
For more information on Qualifications, please visit http://www.opm.gov/policy-data-oversight/classification-qualifications/