48 CFR §334.202

1. (a)An IBR normally should be conducted as a post-award activity. A pre-award IBR may be conducted only if—
   1. (1)The acquisition plan contains documentation that demonstrates the need and rationale for a pre-award IBR, including an assessment of the impact on the source selection schedule and the expected benefits;
   2. (2)The use of a pre-award IBR is approved in writing by the head of the contracting activity prior to the issuance of the solicitation;
   3. (3)The source selection plan and solicitation specifically addresses how the results of a pre-award IBR will be used during source selection, including any weight to be given to it in source evaluation; and
   4. (4)Specific arrangements are made, and budget authority is provided, to compensate all offerors who prepare for or participate in a pre-award IBR; and the solicitation informs prospective offerors of the means for and conditions of such compensation.