The balance of probabilities is the standard applicable in New Zealand in respect of preliminary facts such as compliance with the right of a person charged with an offence to be brought as soon as possible before a court: R v Te Kira  3 NZLR 257, and compliance with the right of persons arrested or detained to consult and instruct a lawyer without delay: Police v Kohler  3 NZLR 129, and the same applies to young people: R v S (CA220/97) (1997) 15 CRNZ 214. There is some fudging of the standard, as it is called the balance of probabilities having regard to the gravity of the particular issue:
“The first issue is whether the Crown must prove the facts necessary to establish admissibility of a statement under s 221(2) [Children, Young Persons, and Their Families Act 1989] to the criminal standard of beyond reasonable doubt. In the High Court, Paterson J appears to have adopted this higher test, citing the judgment of Thorp J in R v Fitzgerald unreported, 30 October 1990, HC Auckland T183/90.
“Fitzgerald concerned compliance with the advice requirements of s 215(1)(f), which must be met before any questioning of a young person is undertaken. It was held that substantial compliance had to be proved to the criminal standard before a statement would be admitted. No argument appears to have been addressed to the issue of standard of proof. Since Fitzgerald this Court has held that in the analogous cases concerning alleged breaches of the New Zealand Bill of Rights Act 1990, the lower standard of proof, or balance of probabilities having regard to the gravity of the particular issue, is to be applied R v Te Kira ... Police v Kohler.... We see no good reason to elevate the test under this legislation [Children, Young Persons, and Their Families Act 1989,ss 221(2)(b), 222(4)], and to add a second exception to the ordinary rule governing incidental trial issues. Proof beyond reasonable doubt is therefore not required.”
We have noted recently the discussion by the Supreme Court of what relevance the gravity of the consequences has to the standard of proof when the standard is the balance of probabilities: Z v Dental Complaints Assessment Committee, blogged 25 July 2008.
There are good reasons to complain that the fudged balance of probabilities should be replaced by the standard of proof beyond reasonable doubt. Particularly so, because in Kohler Cooke P (as he then was), delivering the decision of the Court of Appeal, said:
“The question of the standard of proof required of the prosecution to establish a waiver was raised in argument. Some American and Canadian judgments speak of a "heavy burden'', a "high standard of proof'', a "very high standard''. See for example Miranda at p 475; Moran v Burbine 475 US 412, 439, n 9, 450-452 (1986); and R v Manninen (1987) 34 CCC (3d) 385, 393. In Te Kira this Court determined that, for questions of fact concerning alleged Bill of Rights breaches, once the situation is such that the onus falls on the prosecution to negative a breach, the appropriate standard is the balance of probabilities but with the gravity of the issue borne in mind. We doubt whether in practice this will lead to results different from those that would be reached in Canada and the US. The Te Kira standard should apply on the issue of waiver as well as on other factual issues under the Bill of Rights Act. As already mentioned, the prosecution must fail by that standard here.”
If the results are not going to be different, what is the problem with requiring proof beyond reasonable doubt?
Well, in NZ the position is determined by the Evidence Act 2006, which was drafted in the light – if that's the right word – of the authorities mentioned above. The Act specifies – with the unduly fussy particularity that is currently regarded as good draftsmanship – that a finding that evidence was obtained improperly is to be made on the balance of probabilities: s 30(2)(a).
I can't help wondering whether Lord Cooke would have agreed with the decision of the House of Lords in In re B (blogged here 12 June 2008). I think he would have, and in doing so he would have revised the approach he took in Kohler, above. My current take on this is that the Evidence Act 2006 impedes progress on this point, as has the majority decision in Z, above.
This is not to say that all preliminary facts (those which must be established before other evidence becomes admissible) should be proved to the standard beyond reasonable doubt. There is nothing illogical in requiring the balance of probabilities for these, even where the ultimate issue (guilt) must be proved beyond reasonable doubt. The criteria for admissibility are separate from the criteria for proof of guilt. The choice of standard for proof of preliminary facts is a matter of policy, and in the present context it reflects the importance that the court attaches to compliance with the rights of the accused. In Kohler, above, the Court did not discuss the competing policies or give extended reasons for its choice. Similarly, in R v S, above, the Court simply saw “no good reason” for applying the standard of beyond reasonable doubt, again without policy analysis. Even the Privy Council has decided the issue without extended policy analysis: Smith v R (Jamaica)  UKPC (blogged here 27 June 2008), applying the criminal standard. The reasons for the choice are a mystery.
I say “even” the Privy Council, because the Law Lords, who write their opinions without the assistance of law clerks, are least likely to use a style redolent of the honours dissertation. Posner, in “How Judges Think” (2008), makes this interesting observation (p 221):
“Students are taught to approach judicial opinions as if every word were written by the nominal author – that is, the judge – and the effect is to imbue them with a legalistic outlook, an effect reinforced by their youth (to which ... algorithmic thinking as distinguished from pragmatic or legislative thinking is more congenial than it is to older persons) and by an understandable desire to believe that their steep law school tuition is buying them a set of powerful analytic tools. When they become law clerks it is natural for them to write opinions designed to provide legalistic justifications for their judges' votes. They thus contribute to the mystification of the next student generation.”
In the absence of legalistic justification for the choice of standard of proof of preliminary facts, other than regarding earlier cases as precedents that should (but why?) be followed, there is a need for policy justification, but legal education does not develop policy reasoning.