Max of date, based on different column

i'd like to identify the most recent date of one column, grouped by other column.

i want to identify my bigger "Valuation date" based on "Policy Effective Date", and if is possible assign 1 if is the most recent date, and 0 if not, i couldn't group by dates , this is my formula now:

_z_ValDate = 
CALCULATE(
    MAX(vwLossRunData[ValuationDate]),
    ALLEXCEPT(vwLossRunData,vwLossRunData[EffectiveDate])
)

Thanks !!