When things are going wrong, how do you know whether or not to keep going? That's the question that faced Kabir Shahani of Amperity, a company that, in its early days, missed a huge deadline and seemed unable to develop the technology it needed to thrive. Important, difficult questions had to be answered. Investors wanted to make sure their money wasn't being squandered. And in the end, Kabir learned an important lesson—both about when to keep going, and how to measure success.