"Tom Ogilvy" wrote...
for this specific usage, wouldn't

=SUMPRODUCT(-(A1:A100="A"),-(B1:B100="B"))

Achieve the same and be even "faster" than

=SUMPRODUCT(--(A1:A100="A"),--(B1:B100="B"))

Surprised Mr. Grove or Aladan haven't raised this issue - or have they?
...

Not directly, but you won't find me using ISNUMBER(--whatever) rather than
ISNUMBER(-whatever). I just didn't make the explicit point in previous responses
in which I've done this.

When you know you've got an even number of conditions, you're correct that using
single unary minuses would be better, but in general it's safer to use double
unary minuses. Now, as I've written before, it's not the speed of double unary
minuses I like, it's the fact that due to Excel's operator precendence it's
harder to screw up double unary minuses with typos than it is to screw up the
alternatives ^1, *1, +0. Also, since I read left to right, I prefer my number
type coersions on the left rather than the right of my boolean expressions, and
-- looks nicer than 1* or 0+. Wrapping boolean expressions inside N() is another
alternative, possibly clearer, but it eats a nested function call level, so I
don't use it.

--
To top-post is human, to bottom-post and snip is sublime.