Sumproduct based on 3 conditions in 2 different sheets

[ro801]

Hi
I've had a look around and people seem to managing multiple criteria in different ways. I'm after the most reliable way of counting (for example)the number of episodes that occur between 2 dates (01/01/11 to 31/12/11) which have a measurement in column U of less than 5.0 but also have "sinus" written in column AG.
I've tried multiple combinations, with some fairly sketchy results when compared to an old fashioned count up. Any help would be greatly appreciated.
Owen

 

[VoG]

Hello. You need SUMPRODUCT http://www.xldynamic.com/source/xld.SUMPRODUCT.html

 

[ro801]

Hi Thanks for your reply
I tried SUMPRODUCT as below:
=SUMPRODUCT((Tracking!O3:O9999>=40544)*(Tracking!O3:O9999<=40908)*('Total Data Collection'!U3:U9999<=5)*('Total Data Collection'!AG3:AG9999="sinus"))

This gave a result of 8 when it should've been 0. So not that reliable i guess. Anybody have any opinions of the above, or suggest something different?
Owen