As public awareness rises about big data and the profits companies can make by collecting it, government is coming under greater pressure than ever before to act – to protect users and to regulate fast enough, in particular, to keep up with technological change. This report, “Understanding Big Data: Data Calculus in the Digital Era”, seeks to temper some of the kneejerk reaction toward restriction by presenting a more clear-eyed view of the privacy- and competition-related issues making headlines. “Understanding Big Data” makes use of troves of empirical evidence from China, revealing how upwards of a billion users on e-commerce company Alibaba’s platforms, are making actual choices around data-sharing. It also offers an examination of industry practices, including how enterprises are using technologies like secure multi-party computation (SMPC) and cryptography to anonymize the data-production process and protect users’ personal information. At a time when “data privacy” rules the zeitgeist, this report brings forth some compelling counterfactuals. Turning off the recommendation algorithms to over 600,000 users of a popular e-commerce platform, for example, brought down overall transactions by 86 percent and resulted in only well-known brands getting featured. A comparison of the fraud loss rates on mobile-payments platforms (0.0005%) versus traditional bank credit and debit cards (0.02%) was a reminder that a world without freely flowing big data may now be grossly undesirable. Still, the authors are not so naïve as to suggest a laissez faire approach to governance – the report offers guiding principles for data governance that ensure everyone with a role in the creation of data adheres to the standards of integrity and ethics.