Any idea how the output would be a negative number? I think the value is
right, but the negative doesn't make sense. Thanks.

=SUMPRODUCT(--('Enroll I'!A$2:$A$2921=$B67),--('Enroll
I'!$O$2:$O$2921="NSITE0"),--('Enroll I'!M$2:$M$2921="Yes"),---('Enroll
I'!N$2:$N$2921="Yes"))