  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.
