I have a report that I will be taking over from a co-worker that shows 4 months of Volume.
EX:

Volume

May June July August
3 6 4 9

The last column of the report is to show "trend". Basically if the volume is steadily increasing, the trend column shows an upward pointing arrow. If the volume is steadily decreasing, the trend column shows a downward pointing arrow.
I know, fancy stuff here!
Needless to say, I think this is all ridiculous, but I have no choice in the matter!
My problem comes in when the data is as shown above - all over the place. Is there a formula that I can use to logically figure out the trend?

Howdy. A couple of formulas might help: TREND and FORECAST. Try them and see. I think you need to install the Analysis Toolpak.

Suggest SLOPE function. You might combine it with SIGN(SLOPE(volumes,dates))