Conducting Effective Reference Checks
Someone comfortable asking open-ended questions to obtain information should conduct reference checks that seek opinions. Do not merely contact the human resources department of the candidate's previous employer for a reference. This is especially true when hiring a manager, salesperson, or other key employee, when it will be important to speak with supervisors, subordinates, peers, and sometimes even customers, depending on the nature of the job responsibilities.

As in an interview situation, ask questions designed to elicit specific information. Instead of asking "Was Tom a good performer" ask, "What results did Tom produce?" This is also a good time to gain a different viewpoint on the candidate - such as the individual's relationships with subordinates, management style, and other perspectives. Write up the results of all reference checks in a consistent format, including the date, the name of the person spoken to, and the details provided.

Often, a candidate will offer written letters of reference. While these letters are sometimes helpful, they are typically form letters lacking in details that will aid your decision-making process. Letters of reference are not a substitute for good reference checks. If a candidate is employed, do not call the current employer. If you feel you must have information relating to this job, ask for the name off a former employee of the company.

Source: The HR Answer Book, by Shawn Smith, JD & Rebecca Mazin (AMACOM).