5 U.S.C. § 8115: Determination of wage-earning capacity

(a) In determining compensation for partial disability, except permanent partial disability compensable under sections 8107–8109 of this title, the wage-earning capacity of an employee is determined by his actual earnings if his actual earnings fairly and reasonably represent his wage-earning capacity. If the actual earnings of the employee do not fairly and reasonably represent his wage-earning capacity or if the employee has no actual earnings, his wage-earning capacity as appears reasonable under the circumstances is determined with due regard to—(1) the nature of his injury; (2) the degree of physical impairment; (3) his usual employment; (4) his age; (5) his qualifications for other employment; (6) the availability of suitable employment; and (7) other factors or circumstances which may affect his wage-earning capacity in his disabled condition. (b) Section 8114(d) of this title is applicable in determining the wage-earning capacity of an employee after the beginning of partial disability.