UC Santa Cruz ranks 2nd in the U.S. and 11th overall among the top universities in the world under 50 years old, according to an annual analysis by Times Higher Education (THE).

UCSC ranked at the top (99.9 percentile) in the key citation index that measures the influence of an institution's research.

Times Higher Education uses the same range of 13 performance indicators to rank institutions for its "100 under 50" as it uses for its World University Rankings, a list on which UCSC ranked 136. There, UCSC ranked second in the world for research influence, tied with Rice University, and behind only MIT.

Citation index measures a university's research influence by the number of times its published works are cited by scholars across the globe. The data are drawn from the 12,000 academic journals indexed by Thomson Reuters' Web of Science database and include all indexed journals published between 2007 and 2011.

The research influence indicator, weighted at 30 percent of the overall score, is the single most influential and looks at the role of universities in spreading new knowledge and ideas.

"The citations help show us how much each university is contributing to the sum of human knowledge: they tell us whose research has stood out, has been picked up and built on by other scholars and, most importantly, has been shared around the global scholarly community to push further the boundaries of our collective understanding, irrespective of discipline," THE said in explaining the methodology.

THE said it reduces the weight of subjective indicators for academic reputation and prestige for the younger universities, reasoning that older universities have more time to build a reputation with deeper, wider, "and more established alumni networks with graduates more likely to hold senior positions in universities and society at large, all of which can bolster their reputations."

UC Santa Cruz and UC Irvine, both founded in 1965, were the only U.S. universities to rank in the top dozen overall on the "100 under 50." Irvine was fifth. Pohang University of Science and Technology in South Korea was ranked first. All three held the same positions a year ago.

The principal criteria THE uses are:
•    Research: volume, income and reputation (30 percent);
•    Citations: research influence; (30 percent);
•    Teaching: the learning environment (30 percent)
•    International outlook: people and research (7.5 percent);
•    Industry income: innovation (2.5 percent)

Times Higher Education is a weekly British magazine based in London reporting specifically on news and other issues related to higher education. Its World University Rankings first appeared in 2004.