Calculated Value based on a Checkbox field

Hi All:

        This should be quite straightforward, but for some reason...

        I implement a calculated value with this expression: =IF(fieldName="Yes",1,0)

and the data type returned from this formula is a number with 0 decimal places...

        Something particular about this, is that the fieldName field is a checkbox.

        It doesn't work, I only get 0s for all the values (Yes or No).

        I tryed again changing to =IF(fieldName="Yes","1","0") and data type returned string, but I get the same result...

        Can you realize what I am doing wrong?... It's just that I see it pretty well...

        Ok, thanks.