Even with recent improvements, however, about half of deals larger than $250 million fail to deliver the promised returns. The problem lies in the middle of the deal value chain: commercial due diligence. Only one in three business development executives we surveyed said they are satisfied with how their firms manage deal diligence. Too many executives treat diligence as an audit to confirm what they think they know, rather than a solution to the problem of "I don't know what I don't know." The focus on getting the deal done leads to reliance on conventional wisdom that flows from off-the-shelf information or standard industry research. In fact, diligence is a critical step to test and quantify what seems like a good idea.