Louisiana Code of Evidence Art. 705. Disclosure of facts or data underlying expert opinion; foundation

A. Civil cases. In a civil case, the expert may testify in terms of opinion or inference and give his reasons therefor without prior disclosure of the underlying facts or data, unless the court requires otherwise. The expert may in any event be required to disclose the underlying facts or data on cross-examination.

B. Criminal cases. In a criminal case, every expert witness must state the facts upon which his opinion is based, provided, however, that with respect to evidence which would otherwise be inadmissible such basis shall only be elicited on cross-examination.