Section 270.448  Expert Testimony

a)         If scientific, technical, or other specialized knowledge will assist the ALJ to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training or education may testify and render an opinion.

b)         The party seeking to introduce expert testimony bears the burden of establishing the witness' expertise. The ALJ determines whether the witness is sufficiently qualified as an expert.

c)         The expert may only testify as to matters within his or her area of expertise.

d)         An expert may give an opinion on the ultimate issue in the proceeding.

e)         The facts or data upon which an expert bases an opinion may be those perceived by or made known to the expert at or before the hearing. The facts or data need not be admissible in evidence if they are of a type reasonably relied upon by experts in the particular field in forming opinions upon the subject.

(Source:  Added at 42 Ill. Reg. 9226, effective July 1, 2018)