Expert evidence: you think you're confused!

I came across this ruling of Weinberg J in Australian Retailers Association v Reserve Bank of Australia where he excludes evidence from an academic expert because he just couldn't understand it!

If I am wrong in holding that Professor Farrell’s evidence was insufficiently relevant to warrant admissibility, I would nonetheless exclude that evidence in the exercise of my discretion. I would do so pursuant to s 135 of the Evidence Act, on the basis that, read as a whole, it is confusing. Having attempted, I believe assiduously, to understand the gist of Professor Farrell’s evidence, as set out in his various reports, I regret to say that I cannot make a great deal of sense of considerable parts of that evidence. ...

I have only the vaguest notion of what this [explanation and formula] means. ...

Once again, this [further explanation and formula] means nothing to me. In making that observation, I do not intend to cast any doubts upon Professor Farrell’s technical expertise. Plainly, I am in no position to do so. To be fair, the mathematical formulae set out above were in technical appendices. Perhaps Professor Farrell assumed that any judge hearing a matter of this kind would be able to understand material presented in this manner. If so, he was mistaken, at least as far as I am concerned. I regret to say that evidence presented to a court in this form is likely to be unhelpful, and really should not be adduced. The technical appendices provide a significant part of the rationale for Professor Farrell’s conclusions, which are themselves not altogether easy to follow. Having regard to the difficulty that I have in understanding Professor Farrell’s reasoning, I propose to exclude his evidence in-chief in its entirety. I am prepared, however, to have regard to those parts of his evidence, under cross-examination, that I was able to understand.

See the full extract (including the confusing explanations!) in pdf