Set Analysis

[Anonymous]

i have the following chart which compares values from one year to the next:

The 'Month Year' e.g. 'Dec 2013' are based on the following expression:

=Num(Sum ({$<Year={2013},Month=>} [MedAid Amount] + [Shortfall]), '$##,##0.00')

Since the year 2015 only contains data up to the end of August, growth comparisons with previous year becomes erroneous.  It would be good to base the above on rolling 12 months figures so that like can be compared to like (12 month values) when it comes growth rates.  How can the above expression be modified to calculate rolling 12 months values instead of calendar values?

Regards.

[Anonymous]

Thank you all, managed to sort it out using the PeriodID definition as suggested and linking the calendar and fact table through this PeriodID (Year*12 + Month)