For the first time in almost 20 years, UC Berkeley has not achieved the sole title of No. 1 public university in the United States, as ranked by U.S. News and World Report.

The leader in college rankings placed UC Berkeley at No. 21 on its annual list, tying with UCLA, USC and Emory University. Private universities dominated the top spots in the rankings list.

The list ranks national universities that offer a full range of undergraduate majors, master’s degrees and doctoral programs and that demonstrate a commitment to producing “groundbreaking research,” according to the organization’s website.

Princeton University was ranked the No. 1 school in the country overall, with an undergraduate enrollment of 5,400 and tuition and fees coming in at $47,140. UC Berkeley enrolls 29,311 undergraduates at $42,112 for out-of-state tuition and $14,098 for in-state tuition.

According to Robert Morse, chief data strategist at U.S. News and World Report, the rankings put the most weight on “student outcomes,” at approximately 30 percent. These outcomes include student graduation and retention rate. UC Berkeley performs well in these areas, with a four-year graduation rate of 76 percent and a one-year retention rate of about 97 percent.

The top 20 schools in the rankings, however, were all private universities.

Part of the disparity between public and private universities can be attributed to the rankings criteria, which include academic reputation, student selectivity and alumni giving.

“The criteria really (favor) private schools over public. Some of the public institutions I have talked to were really critical of that,” Politico education reporter Ben Wermund said.

A recent special report by Wermund analyzed the economic disparities between high-ranked universities and those ranked lower in the standings. The study found that many top schools admitted more students from the top 1 percent of earners than those from the bottom 60 percent.

About 17 percent of students at Princeton University were in the top 1 percent of earners, and only about 14 percent of students were in the bottom 60 percent, as of 2011. In contrast, about 5 percent of students at UC Berkeley were from the top 1 percent, and just below 30 percent of students were from the bottom 60 percent.

“This will be the greatest societal challenge of today — trying to make the upward path more accessible,” campus professor emeritus of economics Richard Gilbert said.

According to Morse, nearly 90 percent of people utilizing the rankings are researching universities outside the top 10 schools.

UC Berkeley did not drop any points in any measurement this year, according to campus spokesperson Michael Dirda. He emphasized that UC Berkeley focuses on “twin pillars of access and excellence.”

“We don’t sacrifice that mission to score highly on these rankings,” Dirda said.