Exploring Openness in Data and Science: What is “Open,” to Whom, When, and Why?

\"Open data\" is a popular phrase in research practice and science policy. While stakeholders agree on some aspects of this concept, many others remain hotly debated. As a means to identify the main themes and arguments surrounding open data, we analyzed highly cited publications from the last 10 years that address data sharing or open access to research data. We identify and synthesize eight components of open data that vary among policies, studies, and initiatives, and present problematic arguments worthy of further investigation.