SCS/SB 591 - This act provides that current standards for admitting expert testimony in a civil action shall apply to legal actions adjudicated in probate court, juvenile court, family courts, or in actions involving divorce, marriage, adoption, child support orders, or protective orders. In all other legal actions an expert witness may testify in a court proceeding if the expert has specialized knowledge that will help the trier of fact understand the evidence, the testimony is based on sufficient facts and the product of reliable principles, and if the expert has reliably applied such principles to the facts of the case. An expert may base an opinion on facts in the case that the expert has been made aware of or personally observed. If experts in the particular field would reasonably rely on those kinds of facts in forming an opinion, the facts need not be admissible for the opinion to be admitted. If the facts would otherwise be inadmissible, the proponent may disclose them to the jury only if their probative value outweighs their prejudicial effect. An expert witness shall not testify on the defendant's mental state which constitutes an element of the crime. An expert witness may state an opinion without first testifying to the underlying facts, but may be required to do so on cross-examination. A real property owner is competent to testify as to the reasonable market value of his or her land, in accordance with certain case law listed in the act. This act is similar to HCS/HB 1676 (2016), SCS/SB 233 (2015), HB 697 (2015), and SB 975 (2014). JESSI BAKER