5 ILCS 430/15-20

A violation of this Article may be established only upon a finding that (i) the State employee engaged in conduct described in Section 15-10 and (ii) that conduct was a contributing factor in the retaliatory action alleged by the State employee. It is not a violation, however, if it is demonstrated by clear and convincing evidence that the officer, member, other State employee, or State agency would have taken the same unfavorable personnel action in the absence of that conduct.