Answered by Gigi, Hiring Expert at ADP, on Monday, July 11, 2016
You want the people who will make the strongest recommendations for you. Former supervisors do not have to be references, especially if they did not know all your accomplishments or you fear they will not have glowing things to say about you. Sometimes former co-workers, or supervisors in other departments who know your work, make the best choices. Again, the key is people who know your strengths and abilities and who will say positive things about you.
Overall, you ideally want about three to five references – people who can speak highly of your accomplishments, work ethic, skills, education, performance, etc. For experienced job-seekers, most references should come from previous supervisors and co-workers whom you worked closely with in the past, though you may also choose to list an educational (mentor) or personal (character) reference. College students and recent grads have a little more flexibility, but ideally you should have several references from internships or volunteer work in addition to professors and personal references. Avoid listing family members; clergy or friends are okay for personal references. Former coaches, vendors, customers, and business acquaintances are also acceptable.