2 U.S.C. § 6157

(a) Authorization of expenditure with approval of Committee on Rules and Administration Funds authorized to be expended under section 6155 of this title may be used by the Majority or Minority Conference Committee of the Senate, with the approval of the Committee on Rules and Administration, to procure the temporary services (not in excess of one year) or intermittent services of individual consultants, or organizations thereof, to make studies or advise the committee with respect to any matter within its jurisdiction or with respect to the administration of the affairs of the committee. (b) Procurement by contract or employment Such services in the case of individuals or organizations may be procured by contract as independent contractors, or in the case of individuals, by employment at daily rates of compensation not in excess of the per diem equivalent of the highest gross rate of compensation which may be paid to a regular employee of such committee. Such contracts shall not be subject to the provisions of section 6101 of title 41 or any other provision of law requiring advertising. (c) Selection of consultant or organization by Conference Committee chairman Any such consultant or organization shall be selected for the Majority or Minority Conference Committee of the Senate by the chairman thereof.