Use visualization and mathematics to understand data.
Even the most loathsome criminal can choose to represent himself in court. But data can’t: it needs an advocate to tell its story. Whenever conclusions depend on data, such a story should be told. This will involve performing calculations and visualizing the results. Like good storytelling more generally, data stories should be sensitive to context, including the audience’s expectations. Sometimes simply reporting an average or creating a basic bar chart is compelling enough. Other times much more sophisticated modeling techniques and figures are needed.