sentences:  40 episodes of each program from early 2013 were evaluated, determining that evidence supported 46 percent, contradicted 15 percent and was not found for 39 percent of the recommendations on "The Dr Oz Show".In April 2015, a group of ten physicians from prestigious institutions called for Columbia University to part ways with Oz, who was the vice chair of the Department of Surgery.More than 1,300 doctors signed a letter sent to the university.