After his study was published, in 1999, he met with a coalition of large employers known as the Leapfrog Group.

NEWYORKER: The Checklist

The company works with over 93 percent of the best hospitals in the country, as ranked by U.S. News and World Report and the Leapfrog Group.

FORBES: The Advisory Board Company Finds a Prescription for Business and Social Impact

The Leapfrog Group, a coalition of big corporate health-care purchasers, in 2009 began asking hospitals around the nation to report their rate of early term induced births that weren't medically necessary.

WSJ: Push to Reduce Rates of Early Term Induced Deliveries