Disclosure of facts or data underlying expert opinion

907.05 Disclosure of facts or data underlying expert opinion. The expert may testify in terms of opinion or inference and give the reasons therefor without prior disclosure of the underlying facts or data, unless the judge requires otherwise. The expert may in any event be required to disclose the underlying facts or data on cross-examination. History: Sup. Ct. Order, 59 Wis. 2d R1, R213 (1973); 1991 a. 32.