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Re: Nope

I've been a bit loose with terminology here. DBT means, as you know, that neither the subject nor the person administering the test knows "what's what." But the main point of the analysis I've seen isn't whether the test is double blind; it's how many trials you need to do for a certain positive result ot meet a specified level of confidence. And I BELIEVE the same analysis, more or less, applies whether the test is blind or double-blind. I'd have to brush up; though I remember the conclusions of the work I've studied well enough, the details--even the important ones--elude me at the moment.

I don't know much about the sort of wine competitions you've been involved in, but I would guess that no attempt was made to achieve any sort of statistical rigor, which would be exhausting. Then again, you've got a much harder job; you're trying to determine which is best, where most of the audio related tests--the good ones, anyway--are set up merely to determine whether there is an audible difference. Even for such a modest task it can be difficult--and exhausting--to achieve a high level of statistical confidence in a positive result.

Do you ever do similar trials in wine tasting? Do you ever do an ABX-style test, where participants merely try to determine which of two samples ("A" and "B") are identical the same as the "X" wine (and which is different)? Succeeding just once isn't sufficient in statistical terms; you would have to take the test many times (anyone have the actual numbers in mind or at hand?) and succeed the large majority of the time.

Now imagine that instead of drinking wine out of unmarked cups, you're wiring in a new amplifer and listening to a movement of Beethoven or a Beetles tune. You'll have to remember what the "X" sounds like as you listen to "A" or "B" 10, 12, or more times in succession (listening to the "X" in between as much as you'd like...but keep in mind it can take a while to switch them out). (And by the way, anything but the most well-designed and transparent switch box is likely to be rejected by some judges, since they suspect that it will obscure differences. True? I don't know, but it's possible.)

Qualitative blind tasting like that used (if I understand it) in wine competitions is a great thing. It makes sure that your judgments are not being affected by price tags and labels. But it doesn't constitute statistical proof that one wine is better--or even different--than the other. It just shows that errors will not be due to bias (but there could still be plenty of random error). And that--statistical proof--is what many people require before they will accept that (eg) amplifiers with comparable specs sound different, or that speaker wires have an effect on the sound.

Best,
Jim

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