There’s a big surprise in the 2017 U.S. News MBA ranking out today (March 14).

For only the second time in 28 years, the University of Pennsylvania’s Wharton School fought its way into a tie for first place with Harvard Business School. To capture the top prize, Wharton had to rise three places, jumping over both Stanford University’s Graduate School of Business and the University of Chicago’s Booth School of Business.

The last time Wharton shared first in the U.S. News survey was three years ago when the Philadelphia-based school was in a three-way tie with HBS and Stanford. Wharton administrators have to be breathing a sigh of relief after Booth, building on years of momentum, surpassed the school on the U.S. News list last year for the very first time.

Wharton’s emergence, however, likely has to do more with flaws in U.S. News’ methodology than any major improvements at the school. Wharton was a beneficiary of the way the magazine calculates salary and employment metrics to gain its first place finish (see How Wharton Fought Its Way To The Top Of U.S. News’ 2017 MBA Ranking).

STANFORD SLIP CAUSED BY THE SELF-CONFIDENCE OF ITS OWN GRADS

There are other surprises on this year’s list–and a few shocks. Stanford, despite its highly advantageous geographical location in the most dynamic economy in the world, fell three places to fourth, behind HBS, Wharton and No. 3 Chicago Booth. Stanford’s fall is largely a result of the self-confidence of its MBA graduates who wait longer than peers at other schools to accept their job offers. Only 62.8% of its MBAs were employed by graduation, compared to 85.8% at Wharton, mainly because fewer students are pursuing jobs with mainstream MBA employers, preferring startups and early-stage companies that hire just in time. In all probability, that is also why Stanford slipped in U.S. News’ survey of corporate recruiters, falling behind HBS, Wharton and Chicago Booth among the major employers who complete the survey.

Northwestern University’s Kellogg School and MIT’s Sloan School of Management each climbed one place to finish in a three-way tie with Stanford for the No. 4 spot. New York University’s Stern School of Business, unfairly penalized by U.S. News over a human error in filling out the magazine’s survey last year, climbed back to 12th place from 20th in 2016. Yale’s School of Management, which rose five spots last year to win its highest U.S. News ranking ever, held onto its ninth place finish.

Arizona State University’s W. P. Carey School of Business proved that its strategy of offering full scholarships to every single MBA student has paid off. For the first time ever, Carey cracked the Top 25 list, moving up ten places to 25th from 35 a year ago, thanks to significant improvements in the quality of its incoming cohort of students (see Biggest Winners & Losers In U.S. News’ 2017 MBA Ranking). The University of Southern California’s Marshall School also made big gains, rising seven places to a rank of 24th from 31 in 2016. To make way for Carey and Marshall, two schools fell off the Top 25 list. Rice University’s Jones Graduate School of Business and Notre Dame University’s Mendoza College of Business, both tied at 25th last year, fell into another tie this year to rank 29th.

HOW THE U.S. NEWS’ RANKING WORKS

Besides the drop by Stanford, two other Top 25 schools lost some ground. The University of Virginia’s Darden School of Business and Vanderbilt University’s Owen School of Management both fell three places to finish 14th and 25th, respectively. It’s the second consecutive year that Darden has fallen on the U.S. News list under new Dean Scott Beardsley. The school’s full-time MBA program was ranked tenth only two years ago.

Though the U.S. News ranking fails to assess schools outside the U.S., it is arguably the most watched and followed of all the MBA rankings. The magazine puts a 2018 date on the ranking, even though it is coming out in 2017 and based on 2016 data. That’s largely because of the use of quantiative data on admissions and career outcomes. The methodology takes into account a wealth of proprietary and school-supplied data to crank out its annual ranking of the best full-time MBA programs. The magazine does its own peer assessment survey of B-school deans and MBA directors (25% of the score). It also does its own survey of corporate recruiters (accounting for 15% of the overall ranking). U.S. News said it averaged the recruiter scores over the past three years for the ranking. The magazine reported a 43% response rate for the peer survey but none for the mashup of recruiter polls.

Other metrics included in the ranking are starting salaries and bonuses (14%), employment rates at and three months after graduation (7% to 14%, respectively), student GMATs and GREs scores (about 16%), undergrad GPAs (about 8%), and the percentage of applicants who are accepted to a school (a little over 1%). This is the fifth year U.S. News included GRE scores in its ranking methodology.