"And [PolRef@] what?" is how I read what you've written in your formula. You haven't said how you want to evaluate the polref field in the IF condition, but it doesn't seem like you actually want to. The IF part of an IF condition is evaluation only, it doesn't control any other behaviour.
If you're trying to count the distinct number of pol ref's then you probably want a formula like;
COUNTD( IF stuff THEN [Polref@] END)