Blatch v Archer

A restatement of the obvious: in deciding whether something has been proved on the balance of probabilities, it is important to have regard to the ability of the party who has the onus to lead evidence on a particular matter.

From Ho v Powell (2001) 51 NSWLR 572; [2001] NSWCA 168; BC200103028 at [16]:

[14] There is a long-standing controversy whether the civil standard of proof requires a numerical probability in excess of 50 per cent (see Davies v Taylor [1974] AC 207 at 219), or belief amounting to reasonable satisfaction (see Briginshaw v Briginshaw (1938) 169 CLR 638 at 642-643). My own opinion is that the resolution of the controversy involves recognition that, in deciding facts according to the civil standard of proof, the court is dealing with two questions: not just what are the probabilities on the limited material which the court has, but also whether that limited material is an appropriate basis on which to reach a reasonable decision. I discussed this in some detail in an article published at (1995) 69 ALJ 731.

[15] In considering the second question, it is important to have regard to the ability of parties, particularly parties bearing the onus of proof, to lead evidence on a particular matter, and the extent to which they have in fact done so: cf 69 ALJ at 732-733, 736, 740. As stated by Lord Mansfield in Blatch v Archer (1774) 1 Cowp 63 at 65 (98 ER 969 at 970):

All evidence is to be weighed according to the proof which it was in the power of one side to have produced, and in the power of the other to have contradicted.

Evidence produced by processes, machines and other devices

Section 146 of the Uniform Evidence Acts provides

(1) This section applies to a document or thing—

(a) that is produced wholly or partly by a device or process; and

(b) that is tendered by a party who asserts that, in producing the document or thing, the device or process has produced a particular outcome.

(2) If it is reasonably open to find that the device or process is one that, or is of a kind that, if properly used, ordinarily produces that outcome, it is presumed (unless evidence sufficient to raise doubt about the presumption is adduced) that, in producing the document or thing on the occasion in question, the device or process produced that outcome.


It would not be necessary to call evidence to prove that a photocopier normally produced complete copies of documents and that it was working properly when it was used to photocopy a particular document.

North Sydney Leagues’ Club Limited v Synergy Protection Agency Pty Limited [2012] NSWCA 168 considered the scope of the provision.  At paragraph 63, the Court held:

Section 146 is directed to evidence produced by the application of a mechanical or technological process. Photocopied documents, computer generated material and material generated from data stored in a computer are typical examples. Section 146(2) is not directed to the underlying accuracy of the information contained in a document or record that is produced in this way. For example, s 146(2) has nothing to say about the accuracy of a statement in a photocopied document that $AUD100 was worth $US96. Rather, s 146(2) is a means whereby, on this example, a photocopy of a document containing such information may be received into evidence.

Note also the definition of ‘document’ under the Uniform Evidence Acts, as ‘any record of information’.  The photocopier example in the Acts is therefore probably not the high-water mark of the section’s applicability.  Consider an electronic scale which logs a record of the weight of objects placed on it, and which can print those records.  Suppose the scale contained a record of 1kg having been measured, and the scale prints a record showing a 1kg weighing.  The section should result in not just the conclusion that the printed record reflected the data logged by the scale, but also the fact that 1 kg weight was placed on the scale.  In the words of North Sydney Leagues Club, section 146 should result in the assumption of correctness of the ‘underlying accuracy of the information contained’ in that printed record.

‘Possible’ v ‘probable’

Dahl v Grice appears to be the most recent (c 1974) Victorian authority for the proposition that if expert evidence as to a particular fact is ‘possible’, then the tribunal of fact can (arguably should) take into account any lay evidence and inferences to elevate ‘possible’ to ‘probable’.

The proposition is hardly novel.

Application of the authority would mean that where there are conflicting expert theories, other non-expert evidence may result in the determination of one of those theories as the most probable.