I have historical expenditure data for 8 quarters (previous fiscal yrs) and 3 quarters (current fiscal yr). I'm trying to forecast the next 5 quarters based on historical data. The key is that percentage-wise the trends would be very similar (if not equal). The trending line for the first 8 quarters would mirror the trending line for the next. Since i already have the info for 3 of the 'current' quarters the start of the trend line seems to be parallel to the line of the 'historical' quarters. But I can't figure out how to forecast the next five quarters so that the lines parallel throughout. I've tried the forecast formula within Excel, but have not had any luck. In one row have 8 quarters running accross 8 columns, and in the next row I have 3 quarters running across 3 columns. Any ideas?

thnx,

GiveMePatience (Serenity Now!)

If the data is graphed, it is very simple, just right-click on the data series you want to add the trend info to and choose Add Trendline. The second tab of the ensuing dialog let's you choose how many intervals.

Didn't work well as I hoped. I am trying to get estimated values as well. Thanks for your help anyway.

GMP