The recognized grounds for an appeal are specific legal errors that occurred during trial and affected the outcome: misapplication of the law, abuse of discretion, procedural or evidentiary mistakes, prosecutorial misconduct, jury-related errors, insufficient evidence, and ineffective assistance of counsel. Appellate courts do not retry cases, hear new testimony, or revisit which witnesses the jury believed. They review the existing record for mistakes in how the law was applied or how the proceedings were conducted. A general feeling that the verdict was wrong is not enough. You need to identify a concrete error and show it mattered.
Errors in Applying the Law
The most straightforward ground is that the trial judge got the law wrong. This happens when a judge misinterprets a statute, ignores binding precedent, or applies the wrong legal standard to the facts. A family court judge who skips a required factor in a custody analysis has committed a legal error. So has a judge who uses the wrong test to decide whether a contract was breached. These mistakes matter because appellate courts review pure legal questions from scratch, without deferring to the trial judge’s conclusion. If the appellate court reads the statute differently, the trial judge loses.
Sentencing errors fall into this category and are among the most frequently raised issues in criminal appeals. A judge who miscalculates a sentencing range, applies the wrong guideline, or fails to account for required mitigating factors has made a correctable legal error. The same applies when a sentence exceeds the statutory maximum for the offense.
Abuse of Discretion
Trial judges make dozens of judgment calls during a case, from ruling on evidence disputes to managing the schedule. Appellate courts give these decisions significant breathing room. But when a ruling is so far outside the bounds of reasonable judgment that no competent judge would have made it, it qualifies as an abuse of discretion. Disagreeing with the ruling isn’t enough. You need to show the decision had no rational basis or ignored established legal principles entirely.
Evidentiary rulings are the classic example. A judge who admits testimony from an unqualified expert, excludes evidence central to your defense, or allows highly prejudicial material with little relevance has potentially abused their discretion. The Supreme Court has confirmed that the abuse of discretion standard governs review of evidentiary rulings, including decisions about expert testimony.1Legal Information Institute. Abuse of Discretion The question an appellate court asks is whether the trial judge’s decision was within the range of choices a reasonable judge could have made on those facts.
Procedural and Evidentiary Mistakes
Even when a judge correctly understands the law, the trial itself can go off the rails. Procedural errors focus on whether the process was fair. Did the court follow its own rules for handling motions? Were discovery deadlines enforced evenly? Was a party denied the chance to be heard at a critical stage? When the answer is no, and the mistake affected the result, you have a ground for appeal.
Not every procedural slip matters. Appellate courts distinguish between prejudicial errors and harmless ones. A prejudicial error is one where there’s a reasonable probability the outcome would have been different without the mistake.2United States Courts of Appeals for the Armed Forces. Trial Stages – Appeals – Harmless and Prejudicial Error A harmless error happened but didn’t change anything meaningful. If improperly admitted evidence was cumulative of other testimony the jury already heard, the error is likely harmless. This distinction is where most procedural appeals succeed or fail, and the appellant carries the burden of showing the error mattered.
Constitutional violations are the most serious procedural errors. Due process requires fundamental fairness throughout the proceedings, and courts have found violations in situations involving coerced confessions, denial of the right to confront witnesses, and proceedings tainted by outside pressure or bias.3Legal Information Institute. Criminal Appeals and Procedural Due Process When the claimed error rises to a constitutional violation, the government typically bears the heavier burden of proving the error was harmless beyond a reasonable doubt.
Prosecutorial Misconduct
Prosecutors have enormous power, and with it comes a duty to play fair. The most consequential misconduct involves withholding evidence that could help the defense. The Supreme Court held in Brady v. Maryland that suppressing evidence favorable to the accused violates due process when that evidence is material to guilt or punishment, regardless of whether the prosecutor acted in good faith.4Justia U.S. Supreme Court. Brady v. Maryland, 373 U.S. 83 (1963)
Other forms that can support an appeal include making inflammatory arguments designed to appeal to the jury’s emotions rather than the evidence, commenting on a defendant’s decision not to testify, knowingly presenting false testimony, and improperly coaching witnesses. The key question is whether the misconduct was severe enough to undermine confidence in the verdict. A single offhand remark during closing argument probably won’t do it. A pattern of misleading statements or a hidden piece of exculpatory evidence very well might.
Jury-Related Errors
Before deliberations begin, the judge gives the jury a set of instructions explaining the relevant law and how to apply it. These instructions are the jury’s only official guide, and errors in them can poison the entire verdict. If the judge misstates the elements of an offense, describes the wrong burden of proof, or omits an instruction on a viable defense, the verdict rests on a flawed foundation. Appellate courts read the instructions as a whole, and if the errors were significant enough to produce an unfair trial, the typical remedy is a new one.
Juror misconduct is harder to prove but equally damaging. Jurors who research the case online, discuss it with outsiders, consider evidence not presented in court, or lie during jury selection can compromise the integrity of the verdict. Proving misconduct usually requires concrete evidence, such as a juror’s social media posts or an affidavit from another juror, and you still need to show the misconduct was prejudicial rather than trivial.
Discriminatory jury selection is another ground. Under Batson v. Kentucky, it’s unconstitutional to use peremptory strikes to remove potential jurors based on race, ethnicity, or sex. The rule applies to prosecutors in criminal cases and to private parties in civil cases. A successful challenge generally results in a new trial.
Insufficient Evidence
This ground argues that no reasonable jury could have reached the verdict based on the evidence presented. The standard comes from Jackson v. Virginia: even viewing all the evidence in the light most favorable to the prosecution, could any rational person have found every element of the crime proved beyond a reasonable doubt? If not, the conviction cannot stand. This is deliberately hard to win. The appellate court isn’t reweighing testimony or judging credibility. It’s asking whether the prosecution’s case, taken at its strongest, still falls short on an essential element.
What makes this ground unusual is the remedy. Most successful appeals result in a new trial, giving the other side another shot. But when an appellate court finds the evidence legally insufficient, retrial is off the table. The constitutional protection against double jeopardy prevents the government from trying again after what amounts to a judicial finding that the evidence couldn’t support a conviction. The case is dismissed, and the defendant is effectively acquitted.
In civil cases, a parallel concept exists. If a verdict is against the manifest weight of the evidence, the losing party can argue that the credible evidence so clearly favors the other conclusion that the jury’s decision cannot be allowed to stand. It remains a difficult standard to meet.
Ineffective Assistance of Counsel
The Sixth Amendment guarantees criminal defendants the right to effective legal representation. When a defense attorney’s performance falls far enough below professional standards, the conviction can be challenged. The Supreme Court established the framework in Strickland v. Washington, which requires a defendant to prove two things: that the attorney’s conduct fell below an objective standard of reasonableness, and that there is a reasonable probability the outcome would have been different without those errors.5Justia U.S. Supreme Court. Strickland v. Washington, 466 U.S. 668 (1984)
Both prongs must be satisfied, and courts evaluate the attorney’s decisions with heavy deference. A strategic choice that didn’t pan out is not ineffective assistance. But failing to investigate an obvious alibi witness, sleeping through testimony, missing a filing deadline that forfeits a critical right, or being completely unfamiliar with the relevant law can cross the line. The prejudice prong is where most of these claims die. Even when the attorney’s performance was clearly deficient, the defendant still has to show a reasonable probability that competent representation would have changed the result.
What Does Not Qualify as a Ground
The most common misconception about appeals is that they’re a second chance to argue your case. They aren’t. If the jury weighed conflicting testimony and chose to believe the other side’s witnesses, that decision stands. Appellate courts do not reassess credibility. If you think a witness lied, that’s a factual dispute the jury resolved, not a legal error the appellate court can fix.
New evidence is also off-limits. The appellate record consists of what happened in the trial court, and you cannot introduce documents, testimony, or witnesses that weren’t part of the original proceedings. If genuinely new evidence surfaces after trial, the right vehicle is usually a motion for a new trial filed in the original court, not a direct appeal.
A general sense that the outcome was unfair isn’t a recognized ground. You need to point to a specific legal error and explain how it affected the result.
Preservation and Deadlines Can Still Kill a Valid Ground
Even a strong ground can be lost if the issue wasn’t raised during the trial. This is the preservation requirement, and it catches people off guard. If your attorney didn’t object when problematic evidence was admitted, or didn’t challenge an improper jury instruction before the jury started deliberating, that issue may be waived for purposes of appeal.
Federal Rule of Evidence 103 captures the core principle. To preserve a claim of error about an evidence ruling, a party must make a timely objection or motion to strike and state the specific ground for the objection.6Legal Information Institute. Rule 103 – Rulings on Evidence A vague objection that evidence is “improper” without explaining why isn’t specific enough. Waiting too long can waive the issue entirely.
The one safety valve is the plain error doctrine. When an error is so obvious and so damaging that it threatens the integrity of the judicial process itself, an appellate court can address it even though nobody objected at trial. The error must be clear and obvious, it must have affected the outcome, and correcting it must be necessary to prevent a serious injustice. Courts treat plain error review as a last resort.
Deadlines are the other hard gate. In federal court, a criminal defendant has 14 days after judgment to file a notice of appeal. The standard deadline in a federal civil case is 30 days, extended to 60 days when the federal government is a party.7Legal Information Institute. Rule 4 – Appeal as of Right, When Taken State deadlines vary but commonly fall in the 30-day range. These deadlines are jurisdictional, meaning courts have no discretion to excuse a late filing just because your case is strong. Certain post-trial motions, such as a motion for a new trial, can pause the clock, but only if filed properly and on time.
There’s one more threshold issue. Most appeals can only be taken from a final judgment, meaning a trial court decision that resolves all claims against all parties.8Office of the Law Revision Counsel. 28 U.S. Code 1291 – Final Decisions of District Courts You typically cannot appeal a ruling made in the middle of a case, even if you think the judge got it badly wrong. Narrow exceptions exist for orders involving injunctions, certain collateral rights, and situations where the trial court certifies an issue for immediate review. The general rule is that you wait until the case is over.