For the fourth consecutive year, Princeton University has topped the U.S. News & World Report annual ranking of "America's Best Colleges," this time sharing the top spot with Harvard University, which was second last year.

　　Yale University is ranked third, with the Massachusetts Instituteof Tech-nology fourth. Four schools—the California In-stitute of Technol-ogy, Duke University, Stanford University and the University of Pennsylvania—share the fifth spot.

　　The University of Californi-a-Berkeley and the University of Virginia, tied at No. 21, are the top-rated public universi-ties. Williams College in Williamstown, Mass., is rated the country's best liberalarts college.

　　U.S. News uses a formula that includes graduation and retention rates, faculty re-sources and other factors to de-termine the rankings, which are both popular and contro-versial. Critics have long con-tended that parents and high school students rely far too heavily on U... News in choosing schools, and that col-leges gear some of their efforts toward getting high rankings.