Gharda USA, Inc. and Gharda Chemicals, Ltd. v. Control Solutions, Inc., United Phosphorus, Inc., and Mark Boyd

■ In complex litigation, parties often support their respective positions with expert testimony. Such expert testimony must be both relevant and based on a reliable foundation. Helena Chem. Co. v. Wilkins, 47 S.W.3d 486, 499 (Tex.2001). This case presents the question of whether interdependent opinion testimony from a series of four experts was reliable. The court of appeals held that each expert’s individual testimony was reliable, and therefore the experts’ collective testimony was reliable. 394 S.W.3d 127,169,164 (TexApp. — Houston [1st Dist.] 2012). We hold that the testimony of all four…