Identifying the standard of review for each issue determines how the appeal is argued and often whether it can succeed.
De novo. Questions of law: contract interpretation where the language is unambiguous, statutory construction, subject matter jurisdiction, summary judgment, dismissal on the pleadings, and the legal component of mixed questions. The appellate court owes no deference.
Clear error. Findings of fact after a bench trial. Reversal requires a definite and firm conviction that a mistake has been made. Credibility determinations are close to unreviewable.
Substantial evidence. Jury findings and administrative determinations, viewing the record in the light most favourable to the verdict.
Abuse of discretion. Evidentiary rulings, discovery management, sanctions, continuances, and equitable remedies.
Mixed questions. Reviewed according to whether the inquiry is primarily legal or primarily factual, which is itself an argument worth making.
Strategic consequence. Recharacterising an issue as legal rather than discretionary or factual, where the record fairly permits, is legitimate and frequently decisive. Conversely, an appellee should identify every issue that is reviewed deferentially and say so early in the brief.
Preservation interacts. An unpreserved issue is reviewed, if at all, under a far more demanding standard than the one that would otherwise apply.