Burden of proof
The burden of proof (Latin: onus probandi) is the obligation of a party in a trial to produce the evidence that will prove the claims they have made against the other party.
Criminal vs. Civil
Criminal trials
Beyond a reasonable doubt is the standard for criminals trials. This means the evidence has to eliminate every reasonable doubt. The state prosecutes a person in a criminal trial. The state typically appoints a district attorney who hires prosecutors known as deputy district attorneys (the name might differ from state to state) to carry out prosecutions. Prosecutors have the ability to deny the prosecution of individuals for multiple reasons. Plea deals are also an important part of criminal trials. Most criminal cases in the United States end with plea deals. A plea deal is any agreement in a criminal case between the prosecutor and defendant whereby the defendant agrees to plead guilty or nolo contendere (no contest) to a particular charge in return for some concession from the prosecutor. An example of a plea deal is a a defendant agreeing to plead guilty to a murder charge, in return the prosecutor won't pursue a death penalty against the defendant (in states which apply the death penalty). Judges must approve plea deals and they may deny them if they wish.
Civil cases
Civil cases require less standard of proof than a criminal case. The usual evidence needed is preponderance evidence to secure a win in a civil case. Preponderance is a less standard than beyond a reasonable doubt. This is why in a lot of cases a for instance, a driver might not be found guilty of any criminal charges, however, they might still lose a civil suit and be required to pay a set of amount cash despite not facing any criminal charges. This is because the standard of proof for civil cases is weaker than those for a criminal one..
Legal standards for burden of proof
(From lowest standard to the highest)
Reasonable suspicion
Reasonable suspicion is a low standard of proof to determine whether a brief investigative stop or search by a police officer or any government agent is warranted. It is important to note that this stop or search must be brief; its thoroughness is proportional to, and limited by, the low standard of evidence. In Terry v. Ohio, 392 U.S. 1 (1968), the Supreme Court ruled that reasonable suspicion requires specific, articulable, and individualized suspicion that crime is afoot. A mere guess or "hunch" is not enough to constitute reasonable suspicion.
Probable Cause
Probable cause is a relatively low standard of proof, which is used in the United States to determine whether a search, or an arrest, is warranted. In the criminal context, the U.S. Supreme Court in United States v. Sokolow, 490 U.S. 1 (1989), determined that probable cause requires "a fair probability that contraband or evidence of a crime will be found" in deciding whether Drug Enforcement Administration agents had a reason to execute a search.
Preponderance
Preponderance of the evidence, also known as balance of probabilities, is the standard required in most civil cases and in family court determinations solely involving money, such as child support under the Child Support Standards Act, and in child custody determinations between parties having equal legal rights respecting a child (typically the parents of a child who are divorced, separated, or otherwise living apart, assuming that neither has been found unfit).
Clear and convincing evidence
Clear and convincing evidence is a higher level of burden of persuasion than "preponderance of the evidence". It is employed intra-adjudicatively in administrative court determinations, as well as in civil and certain criminal procedure in the United States. For example, a prisoner seeking habeas corpus relief from capital punishment must prove his factual innocence by clear and convincing evidence. This standard is used in many types of equity cases, including paternity, persons in need of supervision, juvenile delinquency, child custody, the probate of both wills and living wills, petitions to remove a person from life support ("right to die" cases), and many similar cases.
Beyond a reasonable doubt
This is the highest standard used as the burden of proof in Anglo-American jurisprudence and is the standard for convictions in criminal proceedings. Proof beyond a reasonable doubt, therefore, is proof of such a convincing character that one would be willing to rely and act upon it without hesitation in the most important of one's own affairs. However, it does not mean an absolute certainty. Beyond a reasonable doubt means that every reasonable doubt needs to be eliminated for a conviction.
Consider the following three interactions:
no level of suspicion required: a consensual encounter between an officer and citizen
reasonable suspicion required: a stop initiated by the officer that would cause a reasonable person feel not free to leave , subject him to a terry frisk, and might require him to ID.
probable cause required: arrest/search warrants.