The Gulf of Interpretation: From Chart to Message and Back Again

Charts are used to communicate data visually, but designing an effective chart that a broad set of people can understand is challenging. Usually, we do not know whether a chart's intended message aligns with the message readers perceive. In this mixed-methods study, we investigate how data journalists encode data and how a broad audience engages with, experiences, and understands these data visualizations. We conducted a series of workshops and interviews with school students, university students, job seekers, designers, and senior citizens to collect perceived messages and subjective feedback on a sample of eight real-world charts. We analyzed these messages and compared them to the intended message of the chart producer. Four of the collected messages from consumers were then provided to data journalists (including the ones that created the original charts) as a starting point to re-design the charts accordingly. The results from our work underline the difficulty of complex charts such as stacked bar charts and Sankey diagrams. Consumers are often overwhelmed with the amount of data provided and are easily confused with terms (as text) not well known. Chart producers tend to be faithful with data but are willing to abstract further when asked to transport particular messages visually. There are strong conventions on how to visually encode particular information that might not be to the benefit of many consumers.