Notice I put quote marks around the word "simpler"... that was supposed to qualify the word as not being exactly like its definition (and yes, shorter might have been a better word to use).

I'm curious on you last statement... Do you know (or anyone else reading this thread), or is it documented somewhere, how much more efficient we are talking here? I mean, is the percentage difference of adding the calculation for the boolean and then dividing it into 1 to the formula marginal or is it significant?

Not sure if it's documented, I'm sure there have been discussions about it on the forum though.

But to my mind, the difference is significant.

This does a simple binary search

=LOOKUP(9.99999999999999E+307,B4:M4)

It ends up only looking at about half of the cells.

But this formula

=LOOKUP(2,1/(B4:M4<>""),B4:M4)

Must eveluate every cell in the range for <>"", AND perform a devision function on every cell in the range, Then do the same basic binary search.

That is a great formula, for mixed values of numbers and text.

But if it's known that the data is all numeric then the first is much better.

Also, if it's known that the data is all text, then a similar can be done using Rept("z",255) for the lookup value instead of BigNum.