Or. Rev. Stat. § 674.410
A person shall not testify or otherwise present evidence regarding an appraisal or appraisal report in a proceeding under ORS 183.413 to 183.497, a circuit court action or otherwise before a lawfully established board or commission unless the person has prepared a written report on the appraisal or appraisal report prior to presenting testimony or evidence.
[1997 c.417 §7]