Illinois Statutes Chapter 735. Civil Procedure § 5/8-2501. Expert Witness Standards

(a) Relationship of the medical specialties of the witness to the medical problem or problems and the type of treatment administered in the case;

(b) Whether the witness has devoted a substantial portion of his or her time to the practice of medicine, teaching or University based research in relation to the medical care and type of treatment at issue which gave rise to the medical problem of which the plaintiff complains;

(c) whether the witness is licensed in the same profession as the defendant; and

(d) whether, in the case against a nonspecialist, the witness can demonstrate a sufficient familiarity with the standard of care practiced in this State.