Like most large organisations, my employer has 6 month performance reviews. Most of the reviews I have sat through over the past 13 years are based not on facts but by conjecture established by my employer based of my immediate supervisor’s recollections and their involvement in what I have done. Technically my supervisors are involved to a very limited degree in my work (less than 5%). Every time I’m rated good or bad, no factual evidence is given supporting the findings, just hearsay. As the reviews go on to my company record it forms part of work reputation within the organisation and therefore impacts my chances at promotion. Can I sue under Employment Law, and win, for defamation where a negative performance review has been given that is without clear cut evidence?