I've used it before with a friend that shared the same mother plants as myself and roughly grew in the same style, plant count, etc..
Any other bits of info that changed what the actual efficiency was would be brought up in the same discussion. Especially because the discussion was about finding the "best" way to grow in the first place. Lots of pieces are being discussed. Quick veg times were the focus for a while.. then it switched to long veg. Moved around..
It's really just saying how many oz you got under your lights. It's such a simple and dumb'd down way to explain your yield (relating to your light used) that it is both full of flaws AND hard to NOT use at some point.
Putting a name and abbreviation to it is really giving it too much credit.
If I say "I got a LB from my 600" then it is ok.. if i say "I got .74gpw" from my 600 then it's a totally different conversation. It's the same thing, but it's not..
because of this argument, mostly.
Elec is the largest expensive for most cost conscious growers.
It seems reasonable to call it the "unit" of efficiency. Kwh I suppose..
In that case... grams per kwh... prbly a good number to know if you are trying to be really efficient. I've never figured it up, but, i know gpw by 12 thru 22 oz per 600. It's quick stupid math..