The purpose of a conviction appeal is not to retry your case. Appeals are not new trials. You can’t ask the court to hear your evidence again to determine whether you should have been found guilty. An appeal court can only set aside your conviction for one of the following three reasons:

1. The verdict was unreasonable or couldn’t be supported by the evidence.
2. The judge made an error of law.
3. There was a miscarriage of justice on any grounds (basis).

Unreasonable verdict

You may appeal your conviction if the verdict was unreasonable, given the evidence presented. Challenging a conviction on the grounds of an unreasonable verdict focuses only on the weakness of the evidence. You must persuade the appeal court that the evidence was too weak for reasonable jurors to find you guilty beyond a reasonable doubt.

For example, if the only evidence linking an accused person to a bank robbery came from an eyewitness who wasn’t certain she identified the correct person, the appeal court would probably consider changing the conviction.

However, it’s very difficult to succeed on these grounds for appeal. The appeal court is rarely interested in arguments about the credibility of witnesses, or the importance given to various pieces of evidence at the trial. For example, you may think the judge was wrong to believe the Crown’s witnesses instead of you or your witnesses. But that kind of appeal rarely succeeds.

Error of law

You may appeal your conviction because errors of law were made at the trial. If you establish that errors of law were indeed made, your conviction may be set aside. Wrongful admission of evidence, a wrong interpretation of a Charter right, or a misdirection (giving the wrong instructions) to the jury on a crucial question of law are all examples of errors of law.

However, if the court thinks that even without the error the verdict would still have been the same, it won’t allow the appeal. Section 686(1)(b)(iii) of the Criminal Code of Canada permits the court to dismiss an appeal when the verdict couldn’t possibly have been different.

Miscarriage of justice

You may appeal your conviction because of a miscarriage of justice. If there are errors of both fact and law that the appeal court considers to be a miscarriage of justice, your conviction will be set aside. Examples of a miscarriage of justice include a jury member being biased or a judge refusing to provide an interpreter for an accused person who doesn’t understand English very well.