I need to generate a calculated measure that for the period gives the sum of the prior periods for the current year I can use ancestors but that gives all periods for the year - I don't know how to cut it off at the current member sum( {ancestors ([Calendar].[Period Hierarchy].CurrentMember, [Calendar].[Period Hierarchy].[Year]) } ,[Measures].[Amount]) I have a fact table with an ammount and PeriodID and a calenday dimension with a period hierarchy year, quarter, period The period is yyyymm As an extra I also ned the opening balance which has period 200712 There is a period2 hierarchy which has the correct year, and period = yyyy00 for the opening balance.