Is the chart type familiar to your audience (e.g., bar or line chart)?
VisWorkshops Insights from our workshops show that recognizing a chart type helps viewers understand it. In some cases, participants preferred several simple charts over one complex, multi-dimensional visualization.
SemanticContextExperiment When testing how viewers perceive different chart versions, we found that for comparing one-dimensional data, bar charts were perceived as easier to interpret than bubble charts.
VisProducerInterviews Data visualization practitioners spoke in favor of using familiar chart types, such as bar charts, line charts, pie charts and maps, as most frequently used in their work. They acknowledged that more artful designs risk being less understandable for audiences, who would actively request a simpler depiction of the data. Scatterplots and, contradicting others’ preferences, pie charts were named as chart types that some practitioners try to avoid.
Trust in familiar and basic chart types, since the chosen chart type shapes how audiences interpret data. Simple formats like line or bar charts are often easier for lay viewers to understand and can support interpretation.
Could even a simple chart require clarification or guidance to read correctly?
VisLiteracySurvey In a representative* survey, 48% answered at least one of four data-reading tasks incorrectly despite reading from simple bar or line charts. Additionally, roughly every fifth respondent found either bar charts or line charts unfamiliar and an intersection of 12% reported unfamiliarity with both chart types.
*representative sample of Austria’s age groups 18–74 years and their male/female gender split, with n = 438
Be aware that even simple charts can be misread. While familiar chart types help support reading, they should still be questioned for potential ambiguities. Adding clarifying elements, like annotated units, may prevent misinterpretation.
Is the chosen chart type easy to understand for viewers, rather than selected out of habit or convention?
VisWorkshops Interviews and study findings show that complex or high-dimensional charts often overwhelmed viewers and led to misinterpretation, which was the case for Sankey diagrams and stacked bar charts. This also led to wrong conclusions, which is why complex chart types should not be used by convention alone, such as Sankey diagrams for voter behavior.
DomainVisStudy In our study, for visualizing medical network data viewers favored circular designs for their aesthetics. However, performance testing revealed that these visually preferred chart types scored lower in usability compared to simpler options like bar charts and highlights the need to weigh appeal against ease of understanding.
Just because a chart type is widely used or visually appealing, such as in media or reports, does not mean it supports understanding. Convention and aesthetics do not guarantee clarity, so testing alternatives may improve comprehension.
Are maps or geo-referencing used to support spatial understanding where relevant?
CrisisMapSensemaking In our studies, viewers reflected on the crisis maps by contemplating their messages or implementation scenarios. There were different interpretations of the maps’ purposes, but they were commonly seen as a geographical overview and a means to raise awareness about the displayed crisis. Some saw potential for the maps as decision-making tools, useful to government officials.
VisProducerInterviews Several data visualization practitioners stated that their readers love maps above all other chart types. Others shared that comparisons between countries usually work well, according to their usage metrics, which were based, for example, on the number of likes or comments on a post.
Maps are a familiar format that help viewers grasp spatial relationships and relate data to known places. They support understanding of geographical scope and are particularly suitable when location matters to the topic.