In addition to the basic education requirement as stated above, applicants must meet the following to qualify for the GS-12 level: One year of appropriate professional experience that is in or directly related to the duties of the position to be filled is qualifying if it is equivalent to at least the GS-11 level in the Federal service, and if it equipped the applicant with the knowledge, skills and abilities to perform successfully the duties of the position.
Examples of such experience may include planning and executing complex physical science studies, which usually involved intensive investigations into recognized phenomena. This work typically involved conventional methods and techniques though it required going beyond clear precedents, and required adapting methods to the problems at hand and interpreting findings in terms of their scientific significance. At this level, physical scientists have the ability to independently perform scientific work of considerable difficulty.