Good evening --

I have 3 years of reference data stored in worksheets labeled 2008, 2009,
2010 respectively. I would like to allow the user to select a year in cell
F2, and have the formula select the right page for these sumproduct formulas.
That is, everywhere the formula selects page '2008', I'd like it to select
the worksheet based on what's in cell F2. Here's the formula:

=IF(OR(ISBLANK($B12),$B12="TC",$B12=26),SUMPRODUCT (--('2008'!$A$1:$A$20000=$A12),--('2008'!$B$1:$B$20000=$B12),'2008'!$D$1:$D$20000), VLOOKUP($B12,Modifiers,3,FALSE)*SUMPRODUCT(--('2008'!$A$1:$A$20000=$A12),--('2008'!$B$1:$B$20000=""),'2008'!$D$1:$D$20000))

Thanks in advance. I've spent the better part of a day trying to get the
single and double parentheses correct...

Peter