Synopsis As Introduced Amends the Code of Civil Procedure. Provides that a non-expert's opinion or inference testimony is limited to opinions or inferences that are rationally based on his or her perception, helpful to a clear understanding of his or her testimony or the determination of a fact in issue, and not based on scientific, technical, or other specialized knowledge. Sets forth requirements regarding: qualifications, testimony, disclosure, and compensation of expert witnesses; bases of expert opinion testimony; limitations on expert testimony; pre-trial hearings and disclosures concerning expert witnesses; precedents to be followed in interpreting the new provisions; interlocutory appeals of rulings on the admissibility of expert evidence; standards to be followed by reviewing courts in determining the admissibility of expert testimony; severability; and other matters. Applies to actions commenced on or after the effective date of the amendatory Act and pending actions in which a trial has not been scheduled or in which a trial has been scheduled more than 90 days after the effective date of the amendatory Act. Effective immediately.