In the healthcare industry, knowledge driven by big data is changing the shape of research, clinical, and administrative operations; standards of care; and even fundamental business models. It is providing new revenue opportunities previously unattainable in healthcare. Healthcare CIOs are at the center of these groundbreaking initiatives as they struggle to build the business cases for their own programs. However, they often ask Forrester for examples of big data in practice and the resulting ROI behind successful big data initiatives. This report catalogs some major applications of big data Forrester has observed in its research.