Discretionary rulings — evidentiary decisions, discovery management, sanctions, continuances, most equitable remedies — are reviewed for abuse of discretion. The label sounds insurmountable and is not.
What constitutes abuse. A decision based on an erroneous view of the law; a clearly erroneous assessment of the evidence; a failure to consider a factor the law requires; consideration of an improper factor; or a decision outside the range of permissible choices.
Legal error within a discretionary ruling is reviewed de novo. This is the most productive appellate argument in this space: the trial court’s discretion was exercised under a mistaken legal standard, so the standard itself is the issue.
Failure to explain. Where a rule requires findings or the consideration of enumerated factors, a ruling that does not address them may be reversed for that reason alone without the appellate court reaching the merits.
Harmless error applies. An evidentiary error must have affected substantial rights, which requires the appellant to show how the outcome could have differed. Appellants regularly win the error and lose the appeal here.
Preservation matters more under this standard than any other, because the appellate court is assessing the choice the trial judge actually faced on the record before them.