Getting an Error for Using >= in if Statements

Question

I'm trying to write a (checkbox) formula field that looks at the stage name as well as days in a current stage. I am receiving an error that reads: "Incorrect parameter type for operator '>='. Expected Date, received Number"

IF(AND(ISPICKVAL(StageName, 'Initial Interest'), ((TODAY() - Initial_Interest_Date__c) >= 20)), TRUE,
    IF(AND(ISPICKVAL(StageName, 'Qualified Interest'), ((TODAY() - Qualified_Date__c) >= 30)), TRUE,
        IF(AND(ISPICKVAL(StageName, 'Solutioning'), ((TODAY() - Solutioning_Date__c) >= 40)), TRUE,
            IF(AND(ISPICKVAL(StageName, 'Contract Review'), ((TODAY() - Contract_Review_Date__c) >= 30)), TRUE,
                IF(AND(ISPICKVAL(StageName, 'Proposal Sent'), ((TODAY() - Solutioning_Date__c) >= 40)), TRUE,
                    IF(AND(ISPICKVAL(StageName, 'Waiting for Signature'), ((TODAY() - Contract_Review__c) >= 30)), TRUE,
                        FALSE)
                )
            )
        )
    )
)

Could anyone help?

Answer 1

One of the fields was not a date, and a date minus a number is another date, which can't be compared to a number.

Also, you can optimize your formula to be much more readable:

TODAY() -
CASE(StageName,
  'Initial Interest', Initial_Interest_Date__c,
  'Qualified Interest', Qualified_Date__c,
  'Solutioning', Solutioning_Date__c,
  'Contract Review', Contract_Review_Date__c,
  'Proposal Sent', Solutioning_Date__c,
  'Waiting for Signature', Contract_Review__c, 
  TODAY())
>=
CASE(StageName,
  'Initial Interest', 20,
  'Qualified Interest', 30,
  'Solutioning', 40,
  'Contract Review', 30,
  'Proposal Sent', 40,
  'Waiting for Signature', 30, 
  0)

(Note: exact syntax may vary, but this should be close).