Security rule compare form date against table date

I've been working on a security rule for PA52.1 that will restrict specific action codes when the forms effective date (MM/DD/YYYY) is less than the employee's hire date. My returned value from the EMPLOYEE table is in YYYY MonthName DD format.  I've also tried to use the dateFormat function(Date,CurFormat,OutputFormat), but can't find what values are available for use as CurFormat and OutputFormat. Any thoughts or suggestions would be appreciated.