If a United States Federal judge credits critical testimony without fully explaining him or herself, is it subject to appeal?

For example, suppose a judge awards an amount to the winning party because "I found witness C's testimony on X to be credible", would there be grounds to appeal if there are good arguments to be made why C's testimony about X is not credible (say C contradicted himself in other places, etc)

2 Answers 2


First: see How is a judge to evaluate a witness's credibility?

Appealability of credibility findings is extremely limited

A fact-finder's determination of credibility is not an appealable issue unless it can be traced to:

  • an error of law (e.g. if a judge found that a complainant is less worthy of belief because of his or her sexual history); or
  • what is known as a "palpable and overriding error" in Canada or "clear error" in the United States (e.g. the judge based an adverse credibility finding on a piece of evidence that just didn't exist — like the judge writing that the witness said X and Y, but the transcript shows that the witness never said Y).

See footnote 141 of Moffat v Edmonton (City) Police Service, 2021 ABCA 183 for a good summary of the standard in both the US and Canada.

But as long as there is no error of law and no palpable and overriding error (or clear error), credibility findings will not be overturned on appeal. A reviewing court will not simply replace the judge's credibility finding because they would have found differently.

Credibility findings are not all or nothing

Also, credibility findings do not necessitate accepting all or none of a witness's testimony. This is made explicit in typical jury instructions:

you may disregard so much of the testimony as you find was untruthful, and accept so much of it as you find to have been truthful and accurate

Less than full explanation is not the same as completely arbitrary

Last, given your title and introductory paragraph, it seems you may be conflating "completely arbitrary" and not "fully explaining." These are wildly different circumstances. The adequacy of a trial judge's reasons is assessed on a functional basis. The Supreme Court of Canada has said (and this approach is similar elsewhere):

The question is whether the reasons are sufficient to allow for meaningful appellate review and whether the parties’ “functional need to know” why the trial judge’s decision has been made has been met. The test is a functional one.

In determining the adequacy of reasons, the reasons should be considered in the context of the record before the court. Where the record discloses all that is required to be known to permit appellate review, less detailed reasons may be acceptable. This means that less detailed reasons may be required in cases with an extensive evidentiary record, such as the current appeal. On the other hand, reasons are particularly important when “a trial judge is called upon to address troublesome issues of unsettled law, or to resolve confused and contradictory evidence on a key issue”, as was the case in the decision below. In assessing the adequacy of reasons, it must be remembered that “[t]he appellate court is not given the power to intervene simply because it thinks the trial court did a poor job of expressing itself”.

Less than a full explanation does not turn a credibility determination into a completely arbitrary one (e.g. accepting testimony based on a flip of a coin).

  • Thank you for your detailed and wonderful response. Is there appealability for a judge who decides to interpret testimony a particular way where it is unclear that the witness actually meant that? For example, the witness testifies that "I own blue plants", but the judge interprets that as "I wear blue pants" when in reality the witness says later that her blue pants have been in storage since the 70s.
    – lgshost
    Commented Jun 17 at 16:47
  • Ok thanks. I've made it a separate question law.stackexchange.com/questions/103332/…
    – lgshost
    Commented Jun 17 at 17:21
  • So, does the appeal court have the transcript at hand, does the quality and veracity of the court reporter matter (they are a sort of tryer of facts from omissions, commissions and misperceptions and then held as factual) does the reporters previous history become an appealable matter?
    – civitas
    Commented Jun 18 at 12:10

Findings of fact are generally not appealable*

* - as long as they are not obviously unreasonable.

A finder of fact - be it judge or jury - is allowed to weigh credibility as they see fit as long as the result is not totally unreasonable and has any foundation in the testimony and evidence. Contradictions on one topic do not necessarily make the witness in total not credible. It's the same standard as in your previous question, and the same standard applies.

For something that could be appealed, the outcome needs to be far out of the believeable and totally unsupported by any evidence. The Court of Appeals has to give deference to any findings of fact in the previous instance that are reasonable and may only discard findings that are unreasonable and unsupported by admissible evidence.

  • Assume Alice is charged with wearing blue pants. All witnesses (including Alice) state that Alice wore red pants. The Pants in evidence are red. Yet the finder of fact finds Alice wore blue pants based on no evidence. That can be appealed and overturned for a retrial.
  • If in the same case there is even a single piece of evidence or witness that says Alice wore blue pants, and the judge/jury believe that one witness over all others, that is nigh impossible to appeal
    • as long as that testimony is not clearly wrong
    • or inadmissable at that trial. Inadmissibility of evidence (among others: fruit of the poison tree doctrine) can open a question of law review, which in turn can put the finding of fact on shaky grounds later.
  • Still the same charges and same testimony about red or blue pants, but the finder of fact decides that Alice is a dog. That is clearly unreasonable and not even charged, and that verdict should automatically bring a mistrial.

The Standard here is, as Jen notes, "palpable and overriding error", which is comprised of two prongs:

  • palpable - The error or logic followed need to be palpable, which means obvious.
    • In the first example, it's obvious the pants were not blue, so the error is obvious. In the variation, it's unclear which of the witnesses are right, so it would be not obvious.
  • overriding - The error needs to impact the result of the case.
    • In the examples this was ensured by the setup.
  • 1
    Wow. so there is no check on a judge's fact-finding power? Theoretically, a bench-trial judge can pick and choose testimony to get the result he wants?
    – lgshost
    Commented Jun 17 at 8:50
  • 8
    Just as much as any jury can!
    – Trish
    Commented Jun 17 at 9:06
  • 7
    @lgshost If there's contradictory evidence, it's necessary to choose which one to believe. Although this can also constitute reasonable doubt (if the witnesses don't agree on what color her pants were, why should I believe any of them?).
    – Barmar
    Commented Jun 17 at 14:26
  • 1
    @civitas Then the appellate court is the finder of the fact of what was said at the first trial (which is distinct from re-finding the original fact). They may examine the court record and subpoena the participants, and then reach a finding about what was or was not said at the first trial, and whether it supports the trial court's findings in turn.
    – Cadence
    Commented Jun 18 at 19:42
  • 2
    @lgshost Trish's comment "Just as much as any jury can!" can't be overstated. Banish the word "judge" from your brain. Replace it with "finder of fact". Might be a judge or might be a jury. The criteria for appealability apply.
    – RonJohn
    Commented Jun 18 at 21:17

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