Expert Witness Standards in Probate
Section 490.065.1, RSMo governs the admissibility of expert testimony in all proceedings in the probate court. So, this applies to most or all trust and estate litigation, including breach of trust claims and trust contest claims.
Among other things, the statute requires that the facts or data on which the expert relied must be the type reasonably relied upon by experts in the field and “must otherwise be reasonably reliable.” In this context, the testimony is reliable if it is (1) based on widely accepted and peer-reviewed principals and methods, (2) sufficient facts or data, and (3) reliable application thereof. This is generally met so long as there so some independent determination of the reliability of the overall evidence.