When a candidate provides a reference from a current or former employer, ensure that you know what dates this referee actually worked with the candidate. For example: although the candidate may have been employed by an organization from January 2004 until December 2008, they may have only worked with the referee from August 2008 to December 2008.
The latter dates are dates of engagement with that particular reference. Always consider how this may reflect on the responses to the reference questions. When reading the results of the reference interview you are likely to believe you have a clear understanding of their performance over the entire five years and not only over a period of five months. Unless the referee has done their homework when they agreed to provide the reference, by reviewing former performance appraisals and confirming the candidate’s employment start date with Human Resources, they likely are unable to provide detailed answers to questions regarding demonstrated behavior over their entire tenure with that organization.
Let us say this same candidate had dates of engagement with the referee from January 2005 August 2006. You will not have an understanding of their performance for their last two and half years with that employer and you have an employment performance gap. You will either need another reference from that employer or you will need an employment confirmation covering that missing period of time with Human Resources.