The state (aka, "prosecution" or "district attorney") must satisfy the burden of proof necessary for a criminal prosecution. It is important to distinguish the three burdens of proof in court proceedings to understand how much evidence the state must produce to convict a person of a criminal charge.
Preponderance of the Evidence
Preponderance of the evidence means that "the fact to be proven is more probable than not" to have happened. This is an extremely low burden of proof. Preponderance of the evidence is the evidentiary standard at (Department of Motor Vehicle) DMV hearings related to a Driving Under The Influence (DUI) arrest.
The plaintiff, in a civil case, must prove that their version of the facts are more likely to have occurred than the defendant's version.
Clear and Convincing Evidence
Clear and convincing evidence means, "a firm belief or conviction" that an event has occurred. The plaintiff must prove by clear and convincing evidence that his or her version of the facts is more likely to be true than the defendant's version of the facts. This standard falls between preponderance of the evidence and beyond a reasonable doubt.
Clear and convincing evidence is a high burden of proof, however, it is not the highest burden of proof. That belongs to the burden in a criminal proceeding, beyond a reasonable doubt...
Beyond a Reasonable Doubt
The highest burden of proof in any court proceeding is proof "beyond a reasonable doubt." When a person stands trial, the jury must begin with the assumption that the accusations against defendant are false. A juror can only find in favor for the government at the end of the trial if the prosecution has erased all reasonable doubts about the defendant's innocence from the juror's mind.
The "presumption of innocence" is essential to the criminal process. The mere mention of the phrase "presumed innocent until proven guilty" keeps judges and juries focused on the ultimate issue at hand in a criminal case: whether the prosecution has enough evidence to prove beyond a reasonable doubt that the defendant committed the alleged acts.