The health-care system is awash in a sea of data. The tantalizing promise of the Big Data approach is that it could open the door to new methods of unearthing beneficial therapeutics as well as safer and more effective health-care practices. Numerous software, cloud and app developers are diving in to help turn that data into knowledge for improved outcomes. But while we hear a lot about what Big Data is, determining where to invest for the best outcomes remains a bit of a mystery. As technology gets smarter and evolves beyond the basic collection of information to predictive analytics, topological analysis and data-based medical research, what are the smartest ways to assess the impact of our investments? How are the new methods being used for the benefit of patients? And what role should they play in determining value?