Quote Originally Posted by xld
Under the covers, Excel treats TRUE as a 1, and FALSE as a 0. If we perform some arithmetic operation on those values, we can coerce the array of TRUE/FALSE into an array of 1/0. One way is to multiply the resultant array by 1, that is

=SUMPRODUCT((A2:A20="test")*1)

which effectively multiples every test by 1, giving 1 or 0, and stores these values in the resultant array.
How sensible, but I always thought that the numeric values of TRUE and FALSE were 0 and -1 respectively. How did I manage such a basic misconception? Where within Micorsoft's help system does it provide such vital information?