Is there any evidence that they aren't imaginary? For example, does be listed early in one project, lead to improved likelihood of getting a better placement on

Is there any evidence that they aren't imaginary? For example, does be listed early in one project, lead to improved likelihood of getting a better placement on the next project (with corresponding higher future pay)? If that is the case, then the perception that one is a "star" or whatever, with credit order, mind correlate with future success. Of course, that correlation might be independent of credit-order placement (such as the actor is actually better in the movie and would be perceived as such even without credit order placement).