according to david glenn, writing in "the chronicle of higher education", "a majority of economic studies have concluded that file sharing hurts sales". a literature review by professor peter tschmuck found 22 independent studies on the effects of music file sharing. "of these 22 studies, 14 – roughly two-thirds – conclude that unauthorized downloads have a 'negative or even highly negative impact' on recorded music sales. three of the studies found no significant impact while the remaining five found a positive impact."