In 2008 a large scale study concluded that ITQs can help to prevent collapses and restore declining fisheries when compared to a data set including 11,000 fisheries of various management structures (some entirely unmanaged). While nearly a third of open-access fisheries have collapsed, catch share fisheries are only half as likely to fail. However, when compared to other modern fishery management schemes, IFQ managed fisheries exhibit no long term ecological advantages. A study of the 14 IFQ programmes in the United States revealed that fish stocks are unaffected by these management schemes. In terms of productivity, a study that exploits a 2009 reform that introduced IFQ for Peruvian anchovy finds that quotas do not increase within-asset or within-firm productivity in quantities.