Cohort Retention Rate with a twist

[lkhall]

Good morning, 

I have 95% of my Cohort analysis working as expected but there is 1 requirement that I haven't been able to solve. For the cohort retention rate % totals I need to account for the month 0 cohorts that haven't had a chance to reach the given month. As an example shown in attached picture the current month 2 retention rate total calculation is a simple 1098 / 2606 giving you the 42%. But I have to account for the cohorts that haven't reached month 2 so the actual calculation needs to be 1098 / (2606 - 80 - 55) giving you 44%. This calculation would continue on i.e month 3 would then be 969 / (2606 - 80 - 55 -68) = 40%. 

appreciate any help and advice. 

[johnt75]

I think that you could get the total you're after with something like

VAR ChosenCohort = SELECTEDVALUE( 'Cohort'[Num months])
VAR Total = CALCULATE( [My measure], DATEADD( ALLSELECTED('Date'[Date]), -ChosenCohort, MONTH) )

[lkhall]

Thank you very much I think that got me what I needed.