Yesterday I was asked by a graduate student about whom to address a cover letter to when a job listing has no specific person given as the recipient. Here is some practical advice that can help answer that question.
First, if no one’s name is listed, you can always call the secretary of the department to find out who the chair of the search committee is. However, it can be the case that the membership of the search committee has not been solidified at the time the job posting goes out, so you may not be able to get a name even if you try.
If a person’s name is listed: If you know that the person is a PhD, then use “Dear Dr. XXXXXXX,”. If you don’t know or if you are in doubt about it, use “Dear Professor XXXXXXX,”. A comma after the name is appropriate.
If a person’s name is not listed: Use “To the Search Committee:” or “To the Committee:”. A colon after the word “committee” is appropriate in this case.