Customer Retention Calculation Over Successive Weeks

Hi littlemojopuppy ,

Maybe you can add an [Index] and simplify the code.

Users Returning Within 42 Days = 
VAR Weeks = 5
RETURN
    COUNTROWS (
        CALCULATETABLE (
            VALUES ( IdentityLog[IdentityId] ),
            CALCULATETABLE (
                VALUES ( IdentityLog[IdentityId] ),
                DATESINPERIOD (
                    'Calendar'[Date],
                    DATEADD (
                        LASTDATE ( 'Calendar'[Date] ),
                        ( (Weeks- MAX([Index] )* 7 ) + 1,
                        DAY
                    ),
                    7,
                    DAY
                )
            )
    )
)

Best regards,
Lionel Chen

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.