Legal burden of proof
|Part of the common law series|
|Types of evidence|
|Hearsay and exceptions|
|Other common law areas|
The burden of proof (Latin: onus probandi) is the duty of a party in a trial to produce the evidence that will shift the conclusion away from the default position to that party's own position.
The burden of proof is often associated with the Latin maxim semper necessitas probandi incumbit ei qui agit, a translation of which in this context is: "the necessity of proof always lies with the person who lays charges."
The party that does not carry the burden of proof carries the benefit of assumption, an example of which in a criminal case context would be the presumption of innocence. This party needs no evidence to support its claim. Fulfilling the burden of proof effectively captures the benefit of assumption, passing the burden of proof off to another party.
A "burden of persuasion" or "risk of nonpersuasion" is an obligation that remains on a single party for the duration of the court proceeding. Once the burden has been entirely discharged to the satisfaction of the trier of fact, the party carrying the burden will succeed in its claim. For example, the presumption of innocence in a criminal case places a legal burden upon the prosecution to prove all elements of the offense (generally beyond a reasonable doubt), and to disprove all the defenses except for affirmative defenses in which the proof of non-existence of all affirmative defense(s) is not constitutionally required of the prosecution.
The burden of persuasion should not be confused with the evidential burden, or burden of production, or duty of producing (or going forward with) evidence which is an obligation that may shift between parties over the course of the hearing or trial. The evidential burden is the burden to adduce sufficient evidence to properly raise an issue at court.
Standard of proof in the United States
Burden of proof refers most generally to the obligation of a party to prove its allegations at trial. In a civil case, the plaintiff sets forth its allegations in a complaint, petition or other pleading. The defendant is then required to file a responsive pleading denying some or all of the allegations and setting forth any affirmative facts in defense. Each party has the burden of proof of its allegations.
Legal standards for burden of proof
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. A more definite standard of proof (often probable cause) would be required to justify a more thorough stop/search. 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.
An investigatory stop is a seizure under the Fourth Amendment. The state must justify the seizure by showing that the officer conducting the stop had a reasonable articulable suspicion that criminal activity was afoot. The important point is that officers cannot deprive a citizen of liberty unless the officer can point to specific facts and circumstances and inferences therefrom that would amount to a reasonable suspicion. The officer must be prepared to establish that criminal activity was a logical explanation for what he perceived. The requirement serves to prevent officers from stopping individuals based merely on hunches or unfounded suspicions. The purpose of the stop and detention is to investigate to the extent necessary to confirm or dispel the original suspicion. If the initial confrontation with the person stopped dispels suspicion of criminal activity the officer must end the detention and allow the person to go about his or her business. If the investigation confirms the officer's initial suspicion or reveals evidence that would justify continued detention the officer may require the person detained to remain at the scene until further investigation is complete.
Reasonable to believe
In Arizona v. Gant (2009), the United States Supreme Court defined a new standard, that of "reasonable to believe." This standard applies only to vehicle searches after the suspect has been placed under arrest. The Court overruled New York v. Belton and concluded that police officers are allowed to go back and search a vehicle incident to a suspect's arrest only where it is "reasonable to believe" that there is more evidence in the vehicle of the crime for which the suspect was arrested.
There is still an ongoing debate as to the exact meaning of this phrase. Some courts have said it should be a new standard while others have equated it with the "reasonable suspicion" of the Terry stop. Most courts have agreed it is somewhere less than probable cause.
Probable cause for arrest
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. It is also used by grand juries to determine whether to issue an indictment. In the civil context, this standard is often used where plaintiffs are seeking a prejudgement remedy.
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. Courts vary when determining what constitutes a "fair probability": some say 30%, others 40%, others 51%.
A good illustration of this evidence/intrusiveness continuum might be a typical police/citizen interaction. Consider the following three interactions:
- no level of suspicion required: a consensual encounter between officer and citizen
- reasonable suspicion required: a stop initiated by the officer that would cause a reasonable person not to feel free to leave
- probable cause required: arrest.
Some credible evidence
One of the least reliable standards of proof, this assessment is often used in administrative law, and often in Child Protective Services (CPS) proceedings in some states. The "some credible evidence" standard is used as a legal placeholder to bring some controversy before a trier of fact, and into a legal process. It is on the order of the factual standard of proof needed to achieve a finding of "probable cause" used in ex parte threshold determinations needed before a court will issue a search warrant. It is a lower standard of proof than the "preponderance of the evidence" standard. The standard does not require the fact-finder to weigh conflicting evidence, and merely requires the investigator or prosecutor to present the bare minimum of material credible evidence to support the allegations against the subject, or in support of the allegation; see Valmonte v. Bane, 18 F.3d 992 (2nd Cir. 1994). In some Federal Appellate Circuit Courts, such as the Second Circuit, the "some credible evidence" standard has been found constitutionally insufficient to protect liberty interests of the parties in controversy at CPS hearings.
In some appeals from decisions of administrative agencies, the courts apply a "substantial evidence" standard of review of the agency's factual findings. In the United States, for example, if a Social Security Disability Insurance claimant is found "not disabled" (and, therefore, ineligible for benefits) by an Administrative Law Judge (ALJ) and the claimant appeals, both the Appeals Council (the body within the Social Security Administration that hears appeals from decisions of ALJs) and the Federal courts (which, in this type of case, will normally hear an appeal only after the claimant has exhausted all administrative remedies) will look to see whether the administrative law judge's decision was supported by "substantial evidence" or not. Substantial evidence is "more than a mere scintilla. It means such relevant evidence as a reasonable mind might accept as adequate to support a conclusion."
Preponderance of the evidence
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. It is also the burden of proof of which the defendant must prove affirmative defenses or mitigating circumstances in civil or criminal court. In civil court, aggravating circumstances also only have to be proven by a preponderance of the evidence, as opposed to beyond reasonable doubt (as they do in criminal court).
The standard is met if the proposition is more likely to be true than not true. The standard is satisfied if there is greater than fifty percent chance that the proposition is true. Lord Denning, in Miller v. Minister of Pensions, described it simply as "more probable than not." Until 1970, this was also the standard used in juvenile court in the United States.
This is also the standard of proof used when determining eligibility of unemployment benefits for a former employee accused of losing the job through alleged misconduct. In most US states, the employer must prove this case with a preponderance of evidence.
Preponderance of the evidence is the standard of proof used for immunity from prosecution under Florida's controversial stand-your-ground law. The defense must present its evidence in a pre-trial hearing, show that the statutory prerequisites have been met, and then request that the court grant a motion for declaration of immunity. The judge must then decide from the preponderance of the evidence whether to grant immunity. This is a far lower burden than "beyond a reasonable doubt," the threshold a prosecutor must meet at any proceeding criminal trial, but higher than the "probable cause" threshold generally required for indictment.
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.
Clear and convincing proof means that the evidence presented by a party during the trial must be highly and substantially more probable to be true than not and the trier of fact must have a firm belief or conviction in its factuality. In this standard, a greater degree of believability must be met than the common standard of proof in civil actions, which only requires that the facts as a threshold be more likely than not to prove the issue for which they are asserted.
This standard is also known as "clear, convincing, and satisfactory evidence"; "clear, cognizant, and convincing evidence"; and "clear, unequivocal, satisfactory, and convincing evidence", and is applied in cases or situations involving an equitable remedy or where a presumptive civil liberty interest exists.
Beyond reasonable doubt
This is the highest standard used as the burden of proof in Anglo-American jurisprudence and typically only applies in criminal proceedings and when considering aggravating circumstances in criminal proceedings. It has been described, in negative terms, as a proof having been met if there is no plausible reason to believe otherwise. If there is a real doubt, based upon reason and common sense after careful and impartial consideration of all the evidence, or lack of evidence, in a case, then the level of proof has not been met.
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. The standard that must be met by the prosecution's evidence in a criminal prosecution is that no other logical explanation can be derived from the facts except that the defendant committed the crime, thereby overcoming the presumption that a person is innocent unless and until proven guilty.
If the trier of fact has no doubt as to the defendant's guilt, or if their only doubts are unreasonable doubts, then the prosecutor has proved the defendant's guilt beyond a reasonable doubt and the defendant should be pronounced guilty.
The term connotes that evidence establishes a particular point to a moral certainty which precludes the existence of any reasonable alternatives. It does not mean that no doubt exists as to the accused's guilt, but only that no reasonable doubt is possible from the evidence presented. Further to this notion of moral certainty, where the trier of fact relies on proof that is solely circumstantial, i.e., when conviction is based entirely on circumstantial evidence, certain jurisdictions specifically require the prosecution's burden of proof to be such that the facts proved must exclude to a moral certainty every reasonable hypothesis or inference other than guilt.
The main reason that this high level of proof is demanded in criminal trials is that such proceedings can result in the deprivation of a defendant's liberty or even in his or her death. These outcomes are far more severe than in civil trials, in which monetary damages are the common remedy.
Another noncriminal instance in which proof beyond a reasonable doubt is applied is LPS conservatorship.
Beyond the shadow of a doubt
Beyond the shadow of a doubt is the strictest standard of proof. It requires that there be no doubt as to the issue. Widely considered an impossible standard, a situation stemming from the nature of knowledge itself, it is valuable to mention only as a comment on the fact that evidence in a court never need (nor can) reach this level. This phrase, has, nonetheless, come to be associated with the law in popular culture.
Standard of proof in the United Kingdom
In the three jurisdictions of the UK (Northern Ireland; England & Wales; and Scotland) there are only two standards of proof in trials. (There are others which are defined in statutes, such as those relating to police powers.)
The criminal standard was formerly described as "beyond reasonable doubt". That standard remains, and the words commonly used, though the Judicial Studies Board guidance is that juries might be assisted by being told that to convict they must be persuaded "so that you are sure".
The civil standard is 'the balance of probabilities', often referred to in judgments as "more likely than not".
The civil standard is also used in criminal trials in relation to those defences which must be proven by the defendant (for example, the statutory defence to drunk in charge that there was no likelihood of the accused driving while still over the alcohol limit). However, where the law does not stipulate a reverse burden of proof, the defendant need only raise the issue and it is then for the prosecution to negate the defence to the criminal standard in the usual way (for example, that of self-defence).
Prior to the decision of the House of Lords in Re B (A Child)  UKHL 35 there had been some confusion – even at the Court of Appeal – as to whether there was some intermediate standard, described as the 'heightened standard'. The House of Lords found that there was not. As the above description of the American system shows, anxiety by judges to make decisions on very serious matters on the basis of the balance of probabilities had led to a departure from the common law principles of just two standards. Baroness Hale said:
- "70. ... Neither the seriousness of the allegation nor the seriousness of the consequences should make any difference to the standard of proof to be applied in determining the facts. The inherent probabilities are simply something to be taken into account, where relevant, in deciding where the truth lies."
- "72. ... there is no logical or necessary connection between seriousness and probability. Some seriously harmful behaviour, such as murder, is sufficiently rare to be inherently improbable in most circumstances. Even then there are circumstances, such as a body with its throat cut and no weapon to hand, where it is not at all improbable. Other seriously harmful behaviour, such as alcohol or drug abuse, is regrettably all too common and not at all improbable. Nor are serious allegations made in a vacuum. Consider the famous example of the animal seen in Regent’s Park. If it is seen outside the zoo on a stretch of greensward regularly used for walking dogs, then of course it is more likely to be a dog than a lion. If it is seen in the zoo next to the lions’ enclosure when the door is open, then it may well be more likely to be a lion than a dog."
The task for the tribunal then when faced with serious allegations is to recognise that their seriousness generally means they are inherently unlikely, such that to be satisfied that a fact is more likely than not the evidence must be of a good quality. But the standard of proof remains 'the balance of probabilities'.
Other standards for presenting cases or defenses
Air of reality
The "air of reality" is a standard of proof used in Canada to determine whether a criminal defense may be used. The test asks whether a defense can be successful if it is assumed that all the claimed facts are to be true. In most cases, the burden of proof rests solely on the prosecution, negating the need for a defense of this kind. However, when exceptions arise and the burden of proof has been shifted to the defendant, they are required to establish a defense that bears an "air of reality." Two instances in which such a case might arise are, first, when a prima facie case has been made against the defendant or, second, when the defense mounts an affirmative defense, such as the insanity defense.
Evidentiary standards of proof
Depending on the legal venue or intra-case hearing, varying levels of reliability of proof are considered dispositive of the inquiry being entertained. If the subject threshold level of reliability has been met by the presentation of the evidence, then the thing is considered legally proved for that trial, hearing or inquest. For example, in California, several evidentiary presumptions are codified, including a presumption that the owner of legal title is the beneficial owner (rebuttable only by clear and convincing evidence).
In the West, criminal cases usually place the burden of proof on the prosecutor (expressed in the Latin brocard ei incumbit probatio qui dicit, non qui negat, "the burden of proof rests on who asserts, not on who denies"). This principle is known as the presumption of innocence, and is summed up with "innocent until proven guilty," but is not upheld in all legal systems or jurisdictions. Where it is upheld, the accused will be found not guilty if this burden of proof is not sufficiently shown by the prosecution. The presumption of innocence means three things:
- With respect to the critical facts of a case the defendant has no burden of proof whatsoever.
- The state must prove the critical facts of the case to the appropriate level of certainty.
- The jury is not to draw any inferences adverse to the defendant from the fact that he has been charged with a crime and is present in court facing the charges against him.
For example, if the defendant (D) is charged with murder, the prosecutor (P) bears the burden of proof to show the jury that D did indeed murder someone.
- Burden of proof: P
- Burden of production: P has to show some evidence that D had committed murder. The United States Supreme Court has ruled that the Constitution requires enough evidence to justify a rational trier of fact to find guilt beyond a reasonable doubt. If the judge rules that such burden has been met, then it is up to the jury itself to decide if they are, in fact, convinced of guilty beyond a reasonable doubt. If the judge finds there is not enough evidence under the standard, the case must be dismissed (or a subsequent guilty verdict must be vacated and the charges dismissed).
- Burden of persuasion: if at the close of evidence, the jury cannot decide if P has established with relevant level of certainty that D had committed murder, the jury must find D not guilty of the crime of murder
- Measure of proof: P has to prove every element of the offence beyond a reasonable doubt, but not necessarily prove every single fact beyond a reasonable doubt.
However, in England and Wales, the Magistrates' Courts Act 1980, s.101 stipulates that where a defendant relies on some "exception, exemption, proviso, excuse or qualification" in his defence, the legal burden of proof as to that exception falls on the defendant, though only on the balance of probabilities. For example, a person charged with being drunk in charge of a motor vehicle can raise the defence that there was no likelihood of his driving while drunk. The prosecution has the legal burden of proof beyond reasonable doubt that the defendant exceeded the legal limit of alcohol and was in control of a motor vehicle. Possession of the keys is usually sufficient to prove control, even if the defendant is not in the vehicle and is perhaps in a nearby bar. That being proved, the defendant has the legal burden of proof on the balance of probabilities that he was not likely to drive.
- A mere evidential burden did not contravene art.6(2);
- A legal / persuasive burden did not necessarily contravene art.6(2) so long as confined within reasonable limits, considering the questions:
- What must the prosecution prove to transfer burden to the defendant?
- Is the defendant required to prove something difficult or easily within his access?
- What threat to society is the provision designed to combat?
In some cases, there is a reverse onus on the accused. A typical example is that of a hit-and-run charge prosecuted under the Canadian Criminal Code. The defendant is presumed to have fled the scene of a crash, to avoid civil or criminal liability, if the prosecution can prove the remaining essential elements of the offence.
In civil law cases, the "burden of proof" requires the plaintiff to convince the trier of fact (whether judge or jury) of the plaintiff's entitlement to the relief sought. This means that the plaintiff must prove each element of the claim, or cause of action, in order to recover. However, in cases of proving loss of future earning capacity, the plaintiff must prove there is a real or substantial possibility of such a loss occurring.
Civil cases of the U.S. Supreme Court
In Keyes v. Sch. Dist. No. 1, 413 U.S. 189 (1973), the United States Supreme Court stated: "There are no hard-and-fast standards governing the allocation of the burden of proof in every situation. The issue, rather, 'is merely a question of policy and fairness based on experience in the different situations.'" For support, the Court cited 9 John H. Wigmore, Evidence § 2486, at 275 (3d ed. 1940). In Keyes, the Supreme Court held that if "school authorities have been found to have practised purposeful segregation in part of a school system," the burden of persuasion shifts to the school to prove that it did not engage in such discrimination in other segregated schools in the same system.
In Director, Office of Workers' Compensation Programs v. Greenwich Collieries, 512 U.S. 267 (1994), the Supreme Court explained that burden of proof is ambiguous because it has historically referred to two distinct burdens: the burden of persuasion, and the burden of production.
The Supreme Court discussed how courts should allocate the burden of proof (i.e., the burden of persuasion) in Schaffer ex rel. Schaffer v. Weast, 546 U.S. 49 (2005). The Supreme Court explained that if a statute is silent about the burden of persuasion, the court will "begin with the ordinary default rule that plaintiffs bear the risk of failing to prove their claims." In support of this proposition, the Court cited 2 J. Strong, McCormick on Evidence § 337, 412 (5th ed. 1999), which states:
The burdens of pleading and proof with regard to most facts have been and should be assigned to the plaintiff who generally seeks to change the present state of affairs and who therefore naturally should be expected to bear the risk of failure of proof or persuasion.
At the same time, the Supreme Court also recognized "The ordinary default rule, of course, admits of exceptions. ... For example, the burden of persuasion as to certain elements of a plaintiff's claim may be shifted to defendants, when such elements can fairly be characterized as affirmative defenses or exemptions. See, e.g., FTC v. Morton Salt Co., 334 U.S. 37, 44-45 (1948). Under some circumstances this Court has even placed the burden of persuasion over an entire claim on the defendant. See Alaska Dept. of Environmental Conservation v. EPA, 540 U.S. 461 (2004)." Nonetheless, "[a]bsent some reason to believe that Congress intended otherwise, therefore, [the Supreme Court] will conclude that the burden of persuasion lies where it usually falls, upon the party seeking relief."
- Transnational principle of law: Trans-Lex.org
- Barron's Law Dictionary, pp. 55-56 (2nd ed. 1984); Black's Law Dictionary, p. 178 (5th ed. 1979).
- Barron's Law Dictionary, p. 55 (2nd ed. 1984).
- Black's Law Dictionary, p. 178 (5th ed. 1979).
- Patterson v. New York, 432 U.S. 197 (1977)
- Barron's Law Dictionary, p. 56 (2nd ed. 1984).
- See Richardson v. Perales, 402 U.S. 389, 401 (1971), quoting from Consolidated Edison Co. v. NLRB, 305 U. S. 197, 229 (1938).
- Miller v. Minister of Pensions  2 All ER 372
- In re Winship, 397 U.S. 358, 90 S.Ct. 1068 (1970)
- "Florida 'stand your ground' law yields some shocking outcomes depending on how law is applied". Tampa Bay Times.
- Calderon v. Thompson, 523 U.S. 538 (1998). The petitioner, Thomas M. Thompson, a convicted rapist/murderer, was executed on July 14, 1998.
- See, Quinlan v. New Jersey, and Cruzan v. Director, Missouri Department of Health, 497 U.S. 261 (1990).
- See Green v The Queen (1971) 126 CLR 28, 33 Austlii
- s.5 Road Traffic Act 1988; see R. vs Sheldrake)
- "House of Lords - In Re B (Children) (Fc) Appellate Committee Lord Hoffmann Lord Scott of Foscote Lord R". parliament.uk.
- Cal. Evid. Code Section 662, available at http://legalmasters.net/practices/real-estate-law/commonly-referenced-real-estate-statutes-and-regulations/california-evidence-code-sections-660-668/
- "Woolmington v DPP  UKHL 1".
- The critical facts of a criminal case are whether the crime charged was committed and whether the defendant is criminally responsible for the commission of the crime.
- Jackson v. Virginia, 443 U.S. 307 (1979).
- Road Traffic Offenders Act 1988, s.5(2)
- Herring, J. (2004). Criminal Law: Text, Cases, and Materials. Oxford: Oxford University Press. pp. 58–64. ISBN 0-19-876578-9.
- R v. DPP, Ex Parte Kebeline  UKHL 43
- Cooper, S. (2003). "Human Rights and Legal Burdens of Proof". Web Journal of Current Legal Issues. 3.