What is the difference between an eligible list and a referral list?

While the eligible list is comprised of all candidates who pass the exam, the referral list is comprised of those candidates who have been referred for an interview to the hiring department. When a referral list is generated, departments determine the number of candidates they would like to interview. Subsequently, they will receive an even number of candidates from the promotional and open competitive lists based on how many they wish to interview. For example: If a department requests six candidates to interview, they will receive the top three promotional candidates and the top three open competitive candidates.