Data stories — this buzzword links together two different disciplines: computer science and journalism. The new relationship is called data-driven journalism. The emerging product of this relationship: data-based visualization that reveals the story behind the data. However, who produces those “data stories”? A journalist, an information designer, a computer scientist, or a team? New formats often implicate new workflows and a new way of thinking. This paper sets data visualization in the context of online journalism by focusing on the production process. We interviewed 19 experts of German, Swiss, and American media companies: designers, programmers, and journalists. For the analysis of the interviews we used the grounded theory approach. The findings show: The crucial success factor in the production process of data-based visualization in journalism is the attitude that everyone in the team acts as a journalist — no matter whether programmer, designer or statistician. A case study of the New York Times newsroom illustrates our findings.