Job Referencing Question:

The reason you want to give this warning is because it allows you to provide context and framing for what the reference-checker might hear. If you do not, your potential employer may never tell you that the reference is why they rejected you, so the time to speak up is before they place the call. Ideally, you would offer up former co-workers, clients and others who can speak positively about your work and even old copies of performance reviews if you have them. Sometimes the mere offer of these things will provide the reassurance employers are looking for.