The employee who files a complaint has the burden of establishing by a preponderance of the evidence that he or she made a disclosure, participated in a proceeding, or refused to participate, as described under Sec. 708.5, and that such act was a contributing factor in one or more alleged acts of retaliation against the employee by the contractor. Once the employee has met this burden, the burden shifts to the contractor to prove by clear and convincing evidence that it would have taken the same action without the employee's disclosure, participation, or refusal.