Quickly, however, a conflict arose between Wilson and ETS officials over how to handle the problem. "ETS wanted to send a standard neutral test cancellation score letter to the schools," says Wilson. "Scores get cancelled for all kinds of reasons. You could have a brown out. You could have a tech failure. You could have somebody spill Pepsi on a keyboard, or you could have a candidate get sick partway through the test. But they would not change the letter for us to explain why these candidates had their scores cancelled."

　　Furious, Wilson says he personally called the deans of every business school to which the scores were sent and told them the truth. He explained how Xu and his friends were caught and how the scores for the 160 applicants -- retrieved from Xu's computer hard drive -- were bogus. "One dean said, 'That is fascinating," says Wilson. "'We are just now in our boot camp and we can't figure why this one guy who scored well on the test is struggling so much on the easy stuff.' Another guy was doing a summer internship for the dean on ethics." The suspected cheaters weren't corralled, however, because of a lack of evidence.

　　GMAC put the business up for grabs. ETS fought it out with three other rivals and lost its contract. The emerging winner was Pearson VUE, a part of Pearson Plc, the largest commercial testing company and education publisher in the world. Wilson contracted with ACT (American College Testing) based in Iowa for the development of the test, while Pearson took over the administration and distribution of the exam.

　　The break with ETS led to a substantial increase in staff for GMAC. Today, the organization has in-house capability to do test design, research, marketing, and technology support. "We had to start managing our own research to build our own test questions so we added a psychometric group," explains Wilson. "We built a more efficient algorithm for choosing the questions."

　　Wilson successfully fended off an aggressive effort by ETS to grab market share away when it began in 2011 to promote the Graduate Record Examination (GRE) as an alternative to the GMAT. ETS conceded recently that only 2% of surveyed respondents sat for its exam with the objective of applying to an MBA program. Wilson plowed ahead, launching in 2012 a next-generation GMAT exam with a new section called Integrated Reasoning, which measures a candidate's ability to evaluate information. In an R&D effort lasting more than three years and involving dozens of business school deans, admissions officials, faculty, and corporate recruiters, GMAC spent $11 million to get the section into the test.

　　All these changes occurred while GMAC became far more candid than ETS ever was about a test taker's ability to improve their performance on the test. Reminded that ETS used to tell prospective students that they couldn't really study for the exam, Wilson lets out a laugh. "There's no question that you can do better on the test if you study for it. That's a good thing. It's like any sport or any skill." GMAC's own research shows that 60 to 100 hours of study can improve a person's score by an average of 30 points. "There are some who jump by 100 points because they hadn't prepped at all," adds Wilson, who was succeeded as CEO on Jan. 1 by Sangeet Chowfla, a former executive at HP (HPQ).

　　By all accounts, Wilson has done a spectacular job in making GMAC a highly professional organization with a secure financial footing. "I would give him the highest grade you could imagine," says Bill Broesamle, Wilson's predecessor at GMAC. "We had little staff, no infrastructure, and no reach beyond ETS. I think it had run its course. Dave was right to go in a much different direction."

　　For his successor, there is much uncertainty at GMAC. Can the organization find a way to test for innovation and creativity in prospective students? Will the exam survive competition from less expensive alternatives in emerging economies? Will the inevitable unbundling of education through free MOOC courses and online programs lessen the need for an entry exam altogether? If anything, thanks to Wilson, Chowfla has inherited a stable and strong organization with the financial clout to weather a storm.

　　Ask Wilson what his proudest accomplishment is over the 18 years he served as president and CEO and he will immediately give credit to the team he put together. "I managed to find 150 of the best people in the world," he says, "and they have pretty much carried me over the years."

　　But he has also managed to create a significantly larger non-profit, with 30 times the number of employees he inherited, along with some very generously compensated employees. When a prominent business school dean was recently asked to guess what Wilson made in a year, he said about $400,000, which is not much more than one fifth of the reported compensation for GMAC's president and CEO in 2012.