The balance of probabilities

Sometimes, cases that are not quite interesting enough to warrant a blog entry here, nevertheless contain dicta that are worth noting.

Such a case is Sharma v DPP and others (Trinidad and Tobago) [2006] UKPC 57 (30 November 2006). The relatively uninteresting bit of the case is its recognition that a prosecutorial decision to file criminal charges can be subject to judicial review. Here, however, there was insufficient evidence of official misconduct to warrant leave being given to institute review proceedings. While there are some examples of successful reviews of decisions not to prosecute, there is, according to the Privy Council, no English case where a decision to prosecute has been reviewed.

One can understand that absence of example, because the more appropriate recourse would be an application for a stay of proceedings on the grounds that to continue with the prosecution would be an abuse of process.

However, the interesting point I wish to draw attention to in this case concerns what is usually called the civil standard of proof: proof on the balance of probabilities. At para 14 of their joint judgment, Lords Bingham and Walker quoted with approval an English Court of Appeal case, R(N) v Mental Health Review Tribunal (Northern Region) [2005] EWCA Civ 1605, [2006] QB 468 at para 62:

“… the more serious the allegation or the more serious the consequences if the allegation is proved, the stronger must be the evidence before a court will find the allegation proved on the balance of probabilities. Thus the flexibility of the standard lies not in any adjustment to the degree of probability required for an allegation to be proved (such that a more serious allegation has to be proved to a higher degree of probability), but in the strength or quality of the evidence that will in practice be required for an allegation to be proved on the balance of probabilities.”

The standard of proof on the balance of probabilities is frequently used in criminal law in relation to issues such as proof of the defence of insanity, proof of the admissibility of evidence, and proof of an issue by the defence where a statute specifies that that is the standard. It is also applied, exceptionally, to some findings of fact at sentencing, for example proof that specified property was the proceeds of offending.

In some cases the courts have said that the civil standard has the advantage of flexibility: where the issue is a serious one, the standard increases, tending to become akin to proof beyond reasonable doubt for really serious issues. That, it may now be seen, is the wrong way to look at what is going on; the standard is not increased, rather, more cogent evidence is required to satisfy proof on the balance of probabilities, as the issue becomes more serious.

What, one may wonder, is the difference? Well, imagine a case where, at sentencing, the judge has to decide whether certain property represents the proceeds of criminal offending. If it does, a fine may be imposed to represent the value of those proceeds. An illustration is s 39(1)(b) of the Misuse of Drugs Amendment Act 1978[NZ]. In this context, the “fine” is a means of depriving the offender of the benefit of his offending, rather than a punishment, so the civil standard of proof here is appropriate. Nevertheless, the issue is a serious one, especially where the property is valuable and loss of its value may have an adverse effect on innocent people. In the absence of an explanation for how he acquired the property lawfully, the court will be entitled to infer that it was indeed obtained with the proceeds of offending. That may be the ordinary and natural inference, although evidence for it may be slight. It may be a matter of common sense, rather than actual proof. On the other hand, the offender may provide evidence that, for example, at the relevant time he had recently inherited money which he used to pay for the property in question. Unlikely though that explanation may be, he may nevertheless be able to provide cogent evidence in support of his assertion.

Here, if (as is the case) the standard does not increase but the requirement for cogency does, the offender may well be able to establish, on the balance of probabilities, that he did buy the property with inherited money. And, similarly, the prosecution, having a common sense inference but little evidence to back it up, would fail to establish its case on the balance of probabilities. If, however, the seriousness of the issue meant that the standard of proof increased, then, notwithstanding the cogency of his evidence that he inherited the money, the court might still find that the more common sense inference prevailed: while he could establish lawful purchase to a likelihood of, say 51%, he could not reach the higher standard that the circumstances required.

It will be important to get judges to see the difference in these approaches to the meaning of the balance of probabilities. The difference is rather subtle. If the cogency of the required proof increases to a likelihood of, say, 60% in favour, why isn't that an increase in the standard of proof? "Balance" of probabilities suggests a more even contest. Nevertheless, the focus appears to be on the cogency of the evidence for each competing proposition, not on some imaginary shifting standard of proof.

[Update: The European Court of Human Rights rejects the English approach and holds that the strength of the evidence needed to meet the standard of proof does not change with the seriousness of the issue: Saadi v Italy [2008] ECtHR 179 at 140.]