Harvard and Princeton universities remain tied atop the U.S. News & World Report\'s 2013 edition of Best National Universities, the magazine said. There was no change in the No. 1 spot among National Liberal Arts Colleges this year with Williams College, which emphasizes undergraduate education, retaining its top rating. Harvard and Princeton were followed by Yale, Columbia, University of Chicago, Massachusetts Institute of Technology, Stanford, Duke, University of Pennsylvania and California Institute of Technology as the top 10 national universities in the United States. Among national liberal arts colleges, Amherst was No. 2 followed by Swarthmore, Middlebury, Pomona, Bowdoin, Wellesley, Carleton, Haverford and Claremont-McKenna. Vassar jumped up fours spots this year to tie with Claremont-McKenna College. U.S. News said it ranks colleges and universities based on a formula that uses quantitative measures proposed by education experts as reliable indicators of academic quality. The Carnegie Foundation for the Advancement of Teaching\'s classification system provides the basis for the way U.S. News categorizes the schools.