How to calculate a yes/no (binary) variable from date variable

I have a date variable where I want to create a new variable where IF date IS NOT Null THAN "YES' ELSE IF "NO"  

I tried to use DAX create this variable by creating a new column this is what I have

Criteria = IF('Base Population Summary'[Date (11/17)].[Date]null,"NO","YES")

Base Population Summary = Data Tab

Date (11/17) = Date Variable

What is the correct way to write this custom variable?

Thanks

~Bryon