5 CFR §848.202

1. (a)For the purpose of this subpart, working percentage means the percentage of full-time equivalent employment equal to the quotient obtained by dividing—
   1. (1)The number of officially established hours per pay period to be worked by a phased retiree, as described in paragraph (b) of this section; by
   2. (2)The number of hours per pay period to be worked by an employee serving in a comparable position on a full-time basis.
2. (b)The number of officially established hours per pay period to be worked by an employee in phased retirement status must equal one-half the number of hours the phased retiree would have been scheduled to work had the phased retiree remained in a full-time work schedule and not elected to enter phased retirement status. These hours make up the officially established part-time work schedule of the phased retiree and exclude any additional hours worked under § 848.205(j).