On Mon, 13 Dec 2010 08:34:39 -0500, Registered User
wrote:

The phrase "80% antenna efficiency"
contains both a unitless number and dimensional metadata.

Actually, it doesn't - you are filling in the blanks with presumption.
Given that "efficiency" has been hijacked, the phrase above could as
easily relate to wind load. 80% survival rate at 100 mph. I could
well anticipate the counter-argument that "antenna efficiency" as you
intend it is power based, and I would counter-counter that power
delivered to the end user is far below 80% by 6 to 9 orders of
magnitude. There is nothing efficient about 79.999999% of the power
warming clouds and worms. HOWEVER, if the intended recipient receives
even that miniscule power with full quieting, then it is in fact 100%
efficient. In that regard, 80% and 100% as figures become meaningless
when they are both applied to the same statement of efficiency.

In this case
the metadata describes the dimensional calculation used to produce the
result. Remove the dimensional metadata and the phrase becomes "80%".

No, efficiency in engineering terms has always been well understood
and does not embrace this adornment. In an earlier posting I've seen
the distinction of miles-per-gallon and passenger-miles-per-gallon
stretched over the argument to fit it to efficiency. No, these two
comparisons (and what you largely characterize as the need to include
Metadata) are "figure of merit" measures. FOM is also dimensionless
but demands the Metadata you speak of.

FOM could easily lead you into a very energy (the engineering
consideration) inefficient solution (due to social or economic
considerations, eg. passenger-miles-per-gallon).

73's
Richard Clark, KB7QHC