The candidate's immediate supervisor is the source of information most often used. You might also consider contacting the candidate's peers, subordinates and clients. These persons will often have useful information to contribute. Oral vs written sources Another distinction that can be made is between information that is transmitted orally and that which is in writing. Written sources of information, such as performance appraisals and letters of reference, are usually more formal and may be less candid for a variety of reasons.
Oral exchanges are more spontaneous and can sometimes be more revealing.
It is legitimate to use personal knowledge of a candidate on the part of a board member. This information can and should be used even when such information is not available for all candidates. This situation should be treated the same as any reference check, only in this case the particular referee is a member of the board. The board member should relate behaviours rather than opinions. These behavioural descriptions should be recorded as with any other reference check.