In a trial -- whether civil or criminal -- lawyers use evidence to try and prove to a judge or jury that their side should prevail. Evidence comes in a wide variety of forms, ranging from bank records or photographs to a murder weapon or witness testimony. Just as it varies in form, evidence also varies in importance. That which is most important to the issues in a case is called material evidence.
Importance of Evidence
Evidence is material if it is important to deciding a case and is directly related to proving some issue raised during trial. For example, in a murder trial, where the victim died from a .38 caliber gunshot wound, a .38 caliber handgun with the defendant's fingerprints on it would be material evidence. It would link the defendant, the gun and the victim.
Evidence in Criminal Appeals
In a criminal case, certain evidence can mean the difference between freedom and incarceration for a defendant. Occasionally, evidence does not make it into trial because it was hidden or not disclosed by the prosecutor. If the defendant appeals his conviction -- asks a higher court to review the trial -- in a case where the prosecutor withheld evidence, the appeals court decides if the evidence not introduced at trial would likely have changed the result. One example of such evidence is a credible witness who identified someone other than the defendant as the person who committed the crime. Evidence that probably would have changed the outcome of a criminal trial is called material evidence.