THE BEST BUSINESS SCHOOLS 2008 November 11, 2008, 7:22PM EST

How the B-School Rankings are Calculated

The methodology behind BusinessWeek's rankings of the best business schools

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For 20 years, prospective MBA students have turned to BusinessWeek's business school rankings for guidance on finding the best in management education. While business schools themselves have undergone major changes over the years, the rankings have not. The methodology we use measures the level of satisfaction of the schools' two main constituencies—students and corporate recruiters—as well as the intellectual output of faculty at ranked schools.

This year we sent a 50-question survey to 16,704 Class of 2008 MBA graduates at 98 schools in North America, Europe, and Asia. We received 7,264 responses, for a response rate of 46%. Nearly every school helped us contact grads, though the Harvard Business School and the University of Pennsylvania's Wharton School declined to provide student contact information. Using publicly available sources, we were able to reach nearly 32% of the Class of 2008 at those two schools, a significantly lower number than the overall response rate, but enough to make the findings statistically valid.

On the Web-based student survey, grads were asked to rate everything from teaching quality to the effectiveness of career services at their schools on a scale of 1 to 10. The Class of 2008 survey results counts for 50% of a school's total student satisfaction score. An additional 25% comes from our 2006 survey, which polled 16,565 graduates, and 25% from our 2004 survey, which polled 10,074 graduates. Measuring six years' worth of data ensures that short-term improvements or problems don't skew the results. To eliminate outliers, 23 schools were removed from ranking consideration because of low response rates.

Certifying the Student Data

Next we asked David M. Rindskopf and Alan L. Gross, professors of educational psychology at City University of New York Graduate Center, to analyze the data. The idea was to ensure that the results were not skewed by any attempts to influence student responses or otherwise affect the outcome. They tested the responses to verify credibility of the data and to guarantee the poll's integrity. Once the student poll data was certified, the scores received a 45% weight in the overall ranking.

We also invited corporate MBA recruiters to fill out an online survey similar to the one students complete. Because there tend to be greater differences among schools in the corporate survey than in the student poll, recruiter opinion can have a bigger impact on the overall ranking.

Of the 525 companies surveyed, 242 answered, for a response rate of 46%—down from 52% in 2006. Among the companies were those that hire anywhere from a few MBAs each year to those that hire hundreds. In past years, each company was allowed to complete one survey. But this year, to make sure we reached recruiters with in-depth knowledge of European schools, we modified our methodology to allow global companies to complete additional surveys for Europe. That may be one reason why European schools gained prominence in this year's international ranking.

Recruiters were asked to rate their top 20 schools according to the quality of grads and their company's experience with MBAs past and present. Companies could rate only schools at which they have actively recruited in recent years, on campus or off. With the survey completed, we first calculated each school's point total, awarding 20 points for every No. 1 ranking, 19 points for every No. 2 ranking, and so on. Each school's point total was then divided by the number of responding companies that recruited from the school. The resulting 2008 recruiter score was then combined with scores from the 2006 and 2004 recruiter surveys. (The 2008 survey contributes 50% while the 2006 and 2004 polls contribute 25% each.) Combined, the three recruiter polls, like the three student surveys, accounted for 45% of the final ranking.