dissenting.
While I agree this case must be remanded to the district court, I disagree with this court determining the standard of review for the district court to apply. The central issue seized upon by the court is which version of the benefit plan governs: Plan A, from the administrative record, which would necessitate a de novo review, or Plan B, which contains language granting Reliance discretion and would permit an abuse-of-discretion review. Plan B, which the district court used, was not in the administrative record. However, whether Plan B was in the administrative record should not be dispositive of the standard of review. The correct inquiry is which plan was in effect at the time of Barham’s claim. After all, the quest of this court should be a search for the truth, not a search for error.
The court assumes that the administrative record must contain the benefit plan. I agree that both sides should make an accurate and complete record before coming to federal court. Vega v. Nat'l Life Ins. Servs., Inc., 188 F.3d 287, 302 n. 13 *586(5th Cir.1999). When courts review a denial of benefits under an abuse-of-diseretion standard, only the evidence in the administrative record is considered. Sahulka v. Lucent Techs., Inc., 206 F.3d 763, 769 (8th Cir.2000). Even under a de novo review, the introduction of documentation not .in the administrative record is discouraged unless good cause is shown. Ferrari v. Teachers Ins. and Annuity Ass’n, 278 F.3d 801, 807 (8th Cir.2002). However, the vast majority of .case law addresses only whether a plan participant can add documentation to the record which was not before the administrator. See, e.g., id. (discussing .decision not to expand record to include financial documentation offered by plan participant).
The issue of whether a plan must be present in the administrative record has not been squarely addressed by this court. I agree with the Sixth Circuit, which has addressed this issue and determined that the plan need not be present in the administrative record to be considered by the district court. Bass v. TRW Employee Welfare Benefits Trust, 86 Fed.Appx. 848, 851 (6th Cir.2004) (unpublished). The reasons for limiting the record before the district court are to provide for expeditious review and to prevent the district courts from becoming plan administrators. Brown v. Seitz Foods, Inc., Disability Ben. Plan, 140, F.3d 1198, 1200 (8th Cir.1998). Refusing to admit a benefit plan would not advance either of these goals. So, in my view, the district court should be able to review evidence outside the administrative record to determine which plan applies.
The benefit plan which Reliance contends is the correct one was not in the administrative record and was adopted by the district court from Reliance’s brief. Because this is simply an evidentiary dispute, we should remand to the district court to determine which plan and which standard of review to apply to Barham’s claim. Accordingly, I respectfully dissent.