I do think ravi and 2x6 have good points- we're pretty sure, but can't be completely sure, that we can measure everything speaker/amp related.
However, our ear can measure everything audible, including soundstage, effortlessness, smoothness, etc-- so I'd conclude that with much care (which various engineers may or may not take) and technology that's probably fairly close to what we have now, everything true word in a speaker/amp review can be measured.
Reading closely, I do think 2x6 in another recent post about measurements does have a good point about the problems of measurement. Language is tricky...
