Nikki,

It is called the double unary operator. It coerces excel to treat
TRUE/FALSE arrays to 1/0 arrays. 1 being if the condition is TRUE and
0 if the condition is FALSE. That way, if all the conditions are TRUE
the result of the SUMPRODUCT for that row will be 1 and 0 if FALSE so
when it sums it is only counting 1 for each instance that all
conditions are met. This link can explain it more and other uses of
the formula.

Don't worry about the name thing!

HTH

Steve

http://www.xldynamic.com/source/xld.SUMPRODUCT.html


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