INDIRECT Query: How to incorporate INDIRECT to choose between two ranges?

Hi,

I've got a SUMIF formula that looks over a range called 'Budget_Values' but i'd like to be able to switch it to a range called 'Forecast_Values' based on a drop down menu (the only two options are 'Budget' and 'Forecast') in cell A1.

How would I incorporate the INDIRECT function to achieve this? I've tried a couple of different ways but I keep hitting Error City, Arizona

Current formula:

=SUMIF(Budget_Values

Required formula:

=SUMIF(INDIRECT(?



Thanks,

Snook