For the purpose of this subchapter—

(1) the term “statutory pay system” means a pay system under—

(A) subchapter III, relating to the General Schedule;

(B) section 403 of the Foreign Service Act of 1980, relating to the Foreign Service of the United States; or

(C) chapter 74 of title 38, relating to the Veterans Health Administration (other than a position subject to section 7451 of title 38);

(2) the term “ECI” means the Employment Cost Index (wages and salaries, private industry workers) published quarterly by the Bureau of Labor Statistics;

(3) the “base quarter” for any year is the 3-month period ending on September 30 of such year;

(4) the term “pay agent” means the agent designated by the President under section 5304(d)(1);

(5) the term “locality” or “pay locality” means any locality, as established or modified under section 5304;

(6) the term “pay disparity”, as used with respect to a locality, means the extent to which rates of pay payable under the General Schedule are generally lower than the rates paid for the same levels of work by non-Federal workers in the same locality; except as otherwise required in this subchapter, a pay disparity shall be expressed as a single percentage which, if uniformly applied to employees within the locality who are receiving rates of pay under the General Schedule, would cause the rates payable to such employees to become substantially equal (when considered in the aggregate) to the rates paid to non-Federal workers for the same levels of work in the same locality;

(7) the term “comparability payment” means a payment payable under section 5304;

(8) the term “rates of pay under the General Schedule”, “rates of pay for the General Schedule”, or “scheduled rates of basic pay” means the rates of basic pay under the General Schedule as established by section 5332, excluding pay under section 5304 and any other additional pay of any kind; and

(9) the term “General Schedule position” means any position to which subchapter III applies.