One of my longest-standing pet peeves is when litigants and courts consider evidence on appeal, that was not present in the trial court. In Ross v. Blake, Justice Thomas warns against this practice, and says the lower court should decide if the record can be supplemented:

I join the Court’s opinion except for the discussion of Maryland’s prison-grievance procedures, ante, at 11–14, which needlessly wades into respondent Shaidon Blake’s questionable lodgings of new documents in this Court. Those documents are not part of the appellate record. See Fed. Rule App. Proc. 10(a). We have “consistently con- demned” attempts to influence our decisions by submitting “additional or different evidence that is not part of the certified record.” S. Shapiro, K. Geller, T. Bishop, E. Hartnett, & D. Himmelfarb, Supreme Court Practice §13.11(k), p. 743 (10th ed. 2013). Perhaps Blake’s new- found documents are subject to judicial notice as public records. See Fed. Rule Evid. 201. But I would not take such notice for the first time in this Court. It appears that Blake had a chance to submit many of his documents to the lower courts and failed to do so. Taking notice of the documents encourages gamesmanship and frustrates our review. I would let the Court of Appeals decide on remand whether to supplement the record, see Fed. Rule App. Proc. 10(e), or take notice of Blake’s lodgings.

Agreed.