American colleges and universities that are slowly recovering from the country's economical crisis have once again been hit, according to a report by the Times Higher Education magazine. Only eight U.S. universities feature in the '100 Under 50' report which lists the best universities, not more than 50 years old, from around the world.

The magazine arrived at the conclusion after analyzing universities based on their research ability, student-to-faculty ratio and international reputation. South Korea's Pohang University of Science and Technology secured the top spot followed by Switzerland's Ecole Polytechnique Federale of Lausanne and the Korea Advanced Institute of Science and Technology.

The eight American institutions which have made it to the top 100 are all public universities. The two University of California campuses, Irvine and Santa Cruz, and University of Texas at Dallas have been selected in the top 15. Other universities that secured a place in the list include The University of Illinois at Chicago, George Mason University, the University of Maryland, Baltimore County, and the University of Texas at San Antonio.

Phil Baty, editor of the Times Higher Education rankings said that prestigious universities that frequently appear in various best college lists are not the only good-results producing universities. Other colleges that have developed in the recent past are giving a tough competition.

"You get a real strong sense that the world is changing quickly," Baty said. "The U.S. can't rest on its laurels. There are governments that are extremely serious about pumping tens of millions into building world-class universities to challenge the traditional elites."

The report also names 18 U.K. institutions in the top 100 excluding universities from 26 countries like Portugal, Saudi Arabia, New Zealand, Iran, France, Spain and Taiwan. The absentees from the report were India, Russia and mainland China.

Only one online institution has been able to squeeze in to the list - Britain's The Open University, which offers 600 courses ranging from juvenile justice to statistics.

The report also focused its research on the institution's investment on research, how often its faculty's papers are cited around the globe and percentage of international students and staff.