It is the policy of Congress that Federal pay fixing for employees under the General Schedule be based on the principles that—

(1) there be equal pay for substantially equal work within each local pay area;

(2) within each local pay area, pay distinctions be maintained in keeping with work and performance distinctions;

(3) Federal pay rates be comparable with non-Federal pay rates for the same levels of work within the same local pay area; and

(4) any existing pay disparities between Federal and non-Federal employees should be completely eliminated.