In its annual college guide, U.S. News & World Report rates colleges and universities based on up to 15 indicators, including academic reputation, graduation and freshman retention rates, faculty resources, how selective the school is in admitting students and student-faculty ratio.

Each indicator is assigned a value based on the editors’ judgment about how much a measure matters. For instance, the key criteria in judging all of the schools are lowest acceptance rate, highest graduation rate and highest proportion of classes of fewer than 20 students. Then the colleges in each category are ranked against their peers based on their total scores for all indicators.

The 1,400 schools surveyed were divided and ranked in groups of their peers, based on categories developed by the Carnegie Foundation for the Advancement of Teaching:

. National Universities – Doctoral. There are 162 public and 86 private institutions in the country that offer a wide range of undergraduate majors as well as master’s and doctoral degrees. Harvard University and Princeton University tied for top honors in this category this year. The only Maine school in this grouping is the University of Maine, which placed in the third tier of four among a grouping of schools that were lumped together in a ranking between 127 and 190.

. Liberal Arts Colleges – Bachelor’s. The 217 colleges from around the nation in this category emphasize undergraduate education and award at least half of their degrees in liberal arts. Williams College in Massachusetts topped this list. Most Maine schools in this category also fared very well. Bowdoin College ranked 10th, Colby College tied for 17th and Bates College ranked 23rd. College of the Atlantic in Bar Harbor and the University of Maine at Presque Isle both were ranked in the fourth of four tiers.

. Universities – Master’s. The 573 universities in this category provide a full range of undergraduate and master’s programs, but few, if any, doctoral programs. They are ranked against their peers in four geographic areas – North, South, Midwest and West – because they tend to draw students heavily from surrounding states. Villanova University in Pennsylvania headed this group in the North. The University of New England in Biddeford ranked in the second tier between 43 and 86. The University of Southern Maine and St. Joseph’s College in Standish placed in the third tier ranked between 87 and 128. Husson College in Bangor was lumped together with the remaining northern schools in the fourth tier.

. Comprehensive Colleges – Bachelor’s. The 324 institutions in this category also are ranked by region. These schools focus on undergraduate studies and offer a range of degree programs in liberal arts, which account for fewer than half of their bachelor’s degrees, and in professional fields such as business, nursing, and education. Stonehill College in Massachusetts tops this list with the University of Maine at Farmington tied for 12th in the North region. UMF, however, also was ranked best among the public comprehensive colleges in the North. The University of Maine at Machias and Unity College are grouped in the third tier, ranked between 38 and 53. The University of Maine at Augusta and University of Maine at Fort Kent are together with the remaining schools in the fourth tier.