In the spreadsheet that I'm working on, I'm having to use the following array
formula:

{=SUM(IF(('Data Entry'!$A$2:$A$92='Comparitive Chart'!E$1)*('Data
Entry'!$B$2:$B$92='Comparitive Chart'!$C13),1))}

While this works as desired, the problem is that there may be more than 91
entries on the 'Data Entry' page. If I changed it to look at $A:$A instead
of $A$2:$A$92, then the formula returns an error because of all the unused,
blank cells.

I guess what I need is a way to have the formula dynamically look at only
the cells that actually have values, and ignore the rest. There will be no
empty cells in the middle of the list, they will all be at the bottom of the
spreadsheet.

I initially thought to change the formula to look at a cell that counted the
non-blanks by using counta() by changing the formula to read like this(the
referenced cell is z1)

{=SUM(IF(('Data Entry'!$A$2:address($z$1,1)='Comparitive Chart'!E$1)*('Data
Entry'!$B$2:address($z$1,2)='Comparitive Chart'!$C13),1))}

Of course, this didn't work either.