  Professional roles for data visualization designers are growing in
popularity, and interest in relationships between the academic research and
professional practice communities is gaining traction. However, despite the
potential for knowledge sharing between these communities, we have little
understanding of the ways in which practitioners design in real-world,
professional settings. Inquiry in numerous design disciplines indicates that
practitioners approach complex situations in ways that are fundamentally
different from those of researchers. In this work, I take a practice-led
approach to understanding visualization design practice on its own terms.
Twenty data visualization practitioners were interviewed and asked about their
design process, including the steps they take, how they make decisions, and the
methods they use. Findings suggest that practitioners do not follow highly
systematic processes, but instead rely on situated forms of knowing and acting
in which they draw from precedent and use methods and principles that are
determined appropriate in the moment. These findings have implications for how
visualization researchers understand and engage with practitioners, and how
educators approach the training of future data visualization designers.
