5 C.F.R. § 591.210 – What are weights?

(a) A weight is the relative importance or share of a subpart of a group compared with the total for the group. A weight is frequently expressed as a percentage. For example, in a pie chart, each wedge has a percentage that represents its relative importance or the size of the wedge compared with the whole pie.
(b) OPM uses two kinds of weights: Consumer expenditure weights and employment weights.
1. (1) Consumer expenditure weights. The consumer expenditure weight for a category of expenditures (e.g., Food) is the relative importance or share (often expressed as a percentage) of that category in terms of total consumer expenditures. OPM derives consumer expenditure weights from the tabulated results of the Bureau of Labor Statistics (BLS) Consumer Expenditure Survey (CES).
2. (2) Employment weights. The employment weight is the relative employment population of the survey area compared with the employment population of the COLA area as a whole. OPM uses the number of General Schedule employees in the survey area to compute employment weights. OPM uses these employment weights as described in § 591.216(b).