Federal Hiring: OPM Needs to Improve Management and Oversight of Hiring Authorities, GAO-16-521: Published: Aug 2, 2016. Publicly Released: Sep 1, 2016.

“A hiring authority is the law, executive order, or regulation that allows an agency to hire a person into the federal civil service. Of the 105 hiring authorities used in fiscal year 2014, agencies relied on 20 for 91 percent of the 196,226 new appointments made that year. Office of Personnel Management (OPM) officials said they do not know if agencies rely on a small number of authorities because agencies are unfamiliar with other authorities, or if they have found other authorities to be less effective. The competitive examining hiring authority, generally seen as the traditional method for federal hiring, was the single most used authority in fiscal year 2014, but accounted for less than 25 percent of all new appointments.”