Transparency is a fundamental principle of democratic governance. Making government data more widely available promises to enhance organizational transparency, improve government functions, encourage civic engagement, support the evaluation of government decisions, and ensure accountability for public institutions. Furthermore, releases of government data promote growth in the private sector, guiding investment and other commercial decisions, supporting innovation in the technology sectors, and promoting economic development and competition generally. Improving access to government data also advances the state of research and scientific knowledge, changing how researchers approach their fields of study and enabling them to ask new questions and gain better insights into human behaviors. For instance, the increased availability of large-scale datasets is advancing developments in computational social science, a field that is rapidly changing the study of humans, human behavior, and human institutions, and effectively shifting the evidence base of social science. Scientists are also developing methods to mine and model new data sources and big data, and data collected from people and institutions have proven useful in unexpected ways. In the area of public health, Google Flu Trends, which provides a useful and timely supplement to conventional flu tracking methods by analyzing routine Google queries, is a widely publicized example of the unexpected uses of data. These are, of course, just a few examples of the many benefits of open data.