=IF(COUNTIF) Formula I have on database does not work when i sort. HELP PLEASE !!

Providing a small sample spreadsheet with the working state, and then directions on how the sort makes it fail would help. This is probably not the specific issue, but I would probably use MATCH instead of COUNTIF. They may take the same amount of time, but MATCH better states the intent of your formula.

What is likely happening is that after your sort, the formula references moved with the sort. Such that the 'QM Report'!P2, which you expected to 'stay on the same row' after the sort, actually got moved to a different row but still says 'QM Report'!P2.

Since you have Excel 2010, use a Table. Highlight your data and then hit Ctrl-T. Excel will create a Table. Then re-enter that calculation for determining the match, but use the mouse to select the cells you want to use in the equation (i.e. click on cell P2 instead of manually typing in "P2"). This should create something like this:
=IF(COUNTIF('Completed Report'!$G$2:$G$5000,Table1[[#This Row],[YourTableHeader]])>0,"Match","No Match")
or if you switch to MATCH
=IF(ISNA(MATCH(Table1[[#This Row],[YourTableHeader]],'Completed Report'!$G$2:$G$5000,0)),"Not Matched","Matched")

Either way, if you enter the formula in the top row of the table, Excel will magically change the cells below to the new formula (since it is now a Table). Also, since the equation now references Table1[[#This Row],[YourTableHeader]], it will always pull the data from that row, even when the table is sorted or filtered.

Originally Posted by delwatson

=IF(COUNTIF('Completed Report'!$G$2:$G$5000,'QM Report'!P2)>0,"Matched","No Match")

Hello Sean, which sheet is this formula on?