thumb|An example of a chart containing gratuitous chartjunk. This chart uses a large area and much "ink" (many symbols and lines) to show only five hard-to-read numbers, 1, 2, 4, 8, and 16.
Chartjunk consists of all visual elements in charts and graphs that are not necessary to comprehend the information represented on the graph, or that distract the viewer from this information.
Markings and visual elements can be called chartjunk if they are not part of the minimum set of visuals necessary to communicate the information understandably. Examples of unnecessary elements that might be called chartjunk include heavy or dark grid lines, unnecessary text, inappropriately complex or gimmicky font faces, ornamented chart axes, and display frames, pictures, backgrounds or icons within data graphs, ornamental shading and unnecessary dimensions.
Another kind of chartjunk skews the depiction and makes it difficult to understand the real data being displayed. Examples of this type include items depicted out of scale to one another, noisy backgrounds making comparison between elements difficult in a chart or graph, and 3-D simulations in line and bar charts.
thumb|A map of [[North Macedonia with chartjunk: the gradients inside each province do not provide useful information]]
Etymology
The term chartjunk was coined by Edward Tufte in his 1983 book The Visual Display of Quantitative Information
Tufte wrote:
In The Visual Display of Quantitative Information Tufte claims that good design is founded in minimalist design principles. Specifically, he states that "graphics reveal data"
Tufte, in coining the term chartjunk, also made direct comments about a well-known designer at that time, Nigel Holmes. Tufte critiques Holmes' Diamonds chart:
<blockquote>Consider this unsavory exhibit at right – chockablock with cliché and stereotype, coarse humor, and a content-empty third dimension... Credibility vanishes in clouds of chartjunk; who would trust a chart that looks like a video game?</blockquote>
In a 1992 New York Times article, the reporter captures Holmes' response to Tufte's criticism:
<blockquote>Time's Nigel Holmes, creator of the diamonds graph, was understandably irked when Tufte criticized it. Holmes admits his work has sometimes been exaggerated, but feels that Tufte, in his insistence on absolute mathematical fidelity, remains trapped in "the world of academia" and insensitive to "the world of commerce", with its need to grab an audience</blockquote>
This debate between Tufte and Holmes is emblematic of the tension between statistical and designerly approaches to visualization design.
Debate over meaning
The term chartjunk is an umbrella term that can be used to describe a variety of visual devices and has been referenced by different terms across research.
{| class="wikitable"
|+Chartjunk Alternative Terms
!Term
!Citation
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|embellishment
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|excessive annotation
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|decoration
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In a recent study by Parsons and Shukla,