Criminal and civil cases have different legal standards. Most people have heard of the standard “proof beyond a reasonable doubt” in criminal cases. But in most civil cases, the burden of proof is by a “preponderance of evidence.”

The Oregon State Bar Uniform Civil Jury Instruction (UCJI) No. 14.02 instructs juries as follows, “When a party must prove a claim by a preponderance of the evidence, that party must persuade you by evidence that makes you believe the claim is more likely true than not true.” The instruction goes on to read, “After weighing all of the evidence, if you cannot decide that something is more likely true than not true, you must conclude that the party did not prove it. You should consider all of the evidence, no matter who produced it.”

A simpler way to define and visualize preponderance of evidence is with the classic scales of justice. Any tipping of the scales in favor of one party over another– no matter how slight– results in victory for the party who’s scales contain more evidence or more persuasive evidence. If 51% of the evidence is in favor of the plaintiff (the person filing the suit) vs. 49% of the evidence in favor of the defendant (the person defending themselves from the suit), then the plaintiff wins (or “prevails”).

Preponderance of evidence is also used in criminal cases in probation violations (“PVs”) and is virtually identical to the legal standard of “probable cause.”