BOISE, Idaho - In a contentious 3-2 decision on Feb. 14, a majority of the Idaho Supreme Court clarified the law on experts' use of differential diagnosis while the dissent said it overturned established case law and set new rules solely so that the plaintiff in a medical negligence case could prevail (Judy Nield v. Pocatello Health Services, No. 38823-2011, 2014 Opinion No. 20, Idaho Sup.; 2014 Ida. LEXIS 49).