Ian MacMillan says it is better to be "roughly right" than to be "precisely wrong." That is a driving notion behind the BareBones NPV tool that MacMillan, professor of innovation and entrepreneurship at Wharton , and Rita McGrath , who teaches at Columbia University Business School . NPV stands for Net Present Value, and the tool is designed to give innovators and investors a better sense of whether a business idea will generate necessary revenue, and for how long it will remain profitable in a highly competitive business climate. MacMillan explains the tool in this video from Ideas@Wharton: Rita McGrath has more information available on her blog, and provides a downloadable version of the tool here .