You might help your supervisor out by letting her read this. The times have changed:
In 1977, a prospective employer had little difficulty obtaining references for a job applicant from former employers. By 1987 it was another story. Most employers had adopted the policy of providing only the basics: dates of employment, salary, and title. They feared that revealing more information about former employees could expose them to defamation suits by disgruntled former employees unable to find new employment. By 1997, new theories of liability emerged that made a blanket policy of simply giving "name, rank and serial number" of former employees a more dangerous practice. This is especially true when an employer is aware of a former employee’s tendency toward, or history of, violence or sexual misconduct.
Reference-checking has taken on new importance with the dramatic increase in workplace violence. Former employers can be sued for negligent misrepresentation or negligent referral if the employee is involved in some incident at the new workplace that might have been predicted based on prior behavior. Negligent referral or misrepresentation includes the failure to disclose complete and accurate information about former employees. On the other hand, current employers increasingly face the possibility of being sued for negligent hiring if they fail to adequately check the backgrounds of their employees and an employee behaves in some inappropriate manner.
Society at large has an interest in safe workplaces. To help achieve this, thirty-two states so far have passed laws providing varying degrees of immunity to former employers who provide honest references about their former employees. However, it is too early to tell whether the immunity given to employers under these state laws is sufficient protection for them to feel comfortable giving truthful and accurate references about their former employees to prospective employers.
If you want to read the entire article it is at:
http://gbr.pepperdine.edu/992/referral.html