Dist. Ct. erred in granting defendant’s motion for summary judgment in qui tam action alleging that several of defendant’s off-label prescriptions for defendant’s Medicaid patient constituted false claims to U.S. govt. for payment, where said medications were prescribed for purposes not approved by FDA or supported by any pharmaceutical reference books, where basis of ruling was Dist. Ct.’s belief that plaintiff could not establish claim without use of expert to explain Medicaid claim procedures or to interpret certain medical terminology in pharmaceutical reference books. Expert witness was not needed on issue of Medicaid claims procedure since jury could understand that defendant’s writing of improper prescription to Medicaid patient would likely result in claim being filed with Medicaid. Moreover, expert testimony was not necessary to interpret terminology in pharmaceutical reference books where plaintiff’s theory was that there were no medically accepted indication for use of certain drugs to anyone of defendant’s patient’s age. However, on remand, plaintiff may be required to use expert testimony to explain some prescriptions that he claimed constituted false claims, and that he may ultimately not be able to do so since deadline has passed for naming expert witnesses.