Law360, New York ( February 19, 2014, 6:04 PM EST) -- Since Federal Rule of Civil Procedure 26 was amended in 2010, federal appellate courts have been slow to issue guidance about the scope of the attorney work-product protection afforded to expert witnesses and the materials in their files. Parties can reach agreements in advance about the scope of expert discovery — and often do — but when seeking answers after a dispute has ensued, the Ninth Circuit's recent opinion tracks holdings from the Tenth and Eleventh Circuits and gives litigators important guidance: Do not interpret Rule 26 too broadly when addressing expert discovery because the work-product privilege does not presumptively protect materials furnished to or provided by expert witnesses. Rather, it protects from discovery only documents that would disclose attorney opinions, as opposed to the factual basis for the expert's opinion....