=SUMPRODUCT(SUMIF(INDIRECT("'"&C1:C2&"'!I6"),"NP", INDIRECT("'"&C1:C2&"'!I8")
))

where C1:C2 is a range housing the relevant sheetnames in separate cells.


--
HTH

Bob Phillips

(remove xxx from email address if mailing direct)

"frustratedwthis" wrote in
message ...
I am trying to use the following formula to sum the same cell on multiple
sheets IF the critria in another cell on each sheet matches :

=SUMIF('06-01:06-92'I6,NP,'06-01:06-92I8)

I get a return of VALUE.
Can I not use SUMIF to calculate the numbers I need?
Any suggestions?