What it (really) takes to read a chart – TableauFit

How do you preserve a pattern?

Somewhere between 8000 and 7000 BC, humans started keeping a record of their transactions. This person bought 2 bottles of oil, whereas someone else bought 3. Clay tokens served as a way of recording these transactions – consider this a prehistoric receipt. It started out simple enough, tracking just the number. But like tally marks today, the number alone doesn’t clarify what people purchase. Eventually, merchants used various non-descript items to mark not just the amount, but the item itself, creating a clay wallet of sorts. If you’ve ever dug items out of playdoh, you know what happened next: they started including stamping on the outside rather than relying on the contents inside. One day, the marks alone sufficed.

Numeracy shaped the path towards literacy. We outsourced numbers first, because those are harder to remember, particularly at certain scales. Yet, the technology of preserving numbers opened the path to storing ideas and even our exact words. The first writing systems started with vague graphics that resembled ideas, moving closer and closer to logographs for words. As writing systems hit a natural limit of matching pictures to words, they started repurposing the graphics phonetically. Heiroglyphics made use of this hybrid system. Alone, a graphic matched a word, but when combined, it refered back to its phonetic parts. We can replicate this a bit with Bliss Symbols or even emoji.

What does this have to do with charts?

Technologies shift foundational compentancies

Farming created a massive economic shift and encouraged the move to more elaborate contractual practices. Did you agree to trade 3 sheep for this massive haul of wheat? There’s surely a clay token for that. Raising sheep and growing wheat takes time and people needed to know the effort would pan out. Farming as a technology fueled the need to track a variety of numbers from more people. Enter the humble clay token and documented numeracy skills.

Complexity demands nuance. The token system matured, giving us writing. Later writing – such as the formation of alphabets – enabled the writing system to share more about the exact nature of sounds or – in the case of English – greater confusion due to preserving information about the origins of that word. Writing also transformed the culture in ways Socrates feared: it allowed reading to serve as a primary means for getting information. Literacy not only documents ideas, it helps feed new ones.

Clay wallet in the textured shape of a ball and tokens on display in a museum. Ball looks maybe small cantelope sized. 6 tokens are rounded balls (blueberry size) while 2 others are balls that have been smushed (candy size werther's original).
Clay envelope and tokens. Wikipedia.

Today, it is functionally hard to exist in most societies without the ability to read. This wasn’t always the case. Throughout history, literacy served as the dividing line for those of the elite classes and everyone else. Knowledge is power. Technologies like the printing press enabled books to spread, moving reading from a small aristocracy to everyone else.

Reading isn’t just decoding the sounds of the letters, but putting together the whole idea and responding to it. We learn to evaluate the structure, to determine the types of material and its goals, and even engage in conversation around the material. This process takes years with some skills being fully realized in college. Literacy is as much acculturation as it is a skill. A culture steeped in literacy incorporates lines from the prose into the everyday language.

Infographic showing reading stages and maturation as lines by grade level (US American) from 2014 meta analysis on alphabet-based literacy learning:Group 1: Identifying letters and sounds.Letter recognition: 65% Fall K to almost 100% Spring First grade.Beginning sounds: 30% to 99%Ending sounds: 15% to 99% same time period for both. Group 2: Decoding wordsSight words (almost 0 in K, small growth to 25% in Fall 1st and large growth from there to 3rd.Word Comprehension - similar pattern, fall first starting at 10% to 90% by 3rd.Literal inference: Spring 1st 15% to 68% in 3rd and 92% by 8thExtrapolation: 5% in Spring 1st to 45% in 3rd. Gentle arc to 80% in 8th.Last group: understanding and critiquing passagesEvaluation: starts Spring 1st 3% steady rise to 64%Evaluation of nonfiction (3rd 1% soft incline to 33% by 8thLast line: Evaluation of complex syntax starts 5th 0% to 8% in 8th.

Chart reading, or graphicacy, relies on the intersections of technology and a foundational need to understand patterns. We can document the numbers, but they alone are not enough. We can explain in words that we can broadcast and preserve. These, too, are not enough, when what we need to understand is movement.

The sickness was in the air…

Or at least that’s what they told John Snow. Miasma theory traces germs back to bad smells. If it stinks, it sickens. And, in a lot of respects, that’s a good anecdote to have. Yet, it didn’t hold water in the case of cholera.

To understand the pattern, John Snow needed a map. People moved throughout their day, but despite that movement, the sickness concentrated predictably around one central location: the well. Illnesses are vague and we see a ton of charts center around public health for a reason: it’s the only way to move beyond anecdote to antidote by identifying the root cause. Charts provide aggregated lenses. They intersect numbers and words into consolidated images as a third competancy – one that enables the ability to draw meaning from patterns and movement.

Pyrmid showing numeracy at the base, literacy leaning on that, and graphicacy leaning on literacy.
Graphicacy, a 3rd tier skill. Courtesy of Functional Aesthetics for Data Visualization (c) Setlur & yours truly 2022 through Wiley

Like literacy, graphicacy historically remained the domain of the few – residing mostly with a professional class decently versed in statistics. Business intellegence intersected with technology – computers – to make charts rapidly scalable and deployable. What the printing press did for books and literacy, point-and-click chart software enabled charts to move from static presentations to a daily access point.

The Covid-19 pandemic fed a seismic foundational shift on the reliance of charts. In the early days, we sought to “flatten the curve,” a rally cry pulled directly from data visualization. “Flatten the curve” required understanding the shape tied not only to cases, but to two differing scenarios: one around proactive risk mitation and delaying the surge versus the other of continuing status quo responses. The associated graphic abstracted the visuals from a study on 1918 influenza responses from 2 cities, softening their lines and filling the space below. Today, we speak casually of spikes and drops in cases, a nomenclature reliant on understanding the shape the numbers make.

2 charts, side by side labelled as Figure 4.4.First a line chart showing a comparison between Philadelphia and St. Loius in influenza cases in 1918. Phily has a large spike of over 250 flu cases in one week (Oct 19) while St. Louis has gradual include that remains under 50 until the week of Dec 14 with maybe 75 cases. Next to this chart is a "Flatten the curve" icon with 2 hills - one with a massive spike earlier on and the other 1/3 the height with an incline in the middle.
Courtesy of Functional Aesthetics for Data Visualization (c) Setlur & Cogley 2022 through Wiley

We are drawing primary knowledge from charts and having its nuances steep into everyday language. Like numeracy and literacy, graphicacy informs the dialogue, creating rich idioms tied to its form.

Moving beyond the Basics

Intermediate reading moves from beyond the individual words to developing a complex system of understanding new vocabulary (inference), sentences (extrapolation), and ultimately the broader picture (the “evaluation” stage and beyond). Functional literacy – where one can reasonably navigate the written word – demands understanding the intent behind the words. When we learn to evaluate books – such as their styles and voice – we’re parsing beyond the perceptual piece (text) using semantics (meaning) to determine intent.

Functional graphicacy also demands moving beyond learning an exact repetiore of charts (words) to developing an understanding of the semantics that creates graphics. Semantics are the part that recognizes lines generally infer trends or movement while bars typically offer a more discrete point-in-time contrast. The marks work together with the auxilliary design elements (such as gridlines) to showcase intent using their semantic systems to draw meaning.

It doesn’t stop at the chart. These days, the charts are part of a broader composition. More than charts on a page, they are assembled to create narratives, to display nuance off each other, and interwoven with text and numbers to craft both scale (numbers) and detail (words).

Reading relies on the interplay of perception and semantics to determine intent. We perceive the text using our medium of choice: print, Braille, or audio. From there, we draw meaning from the larger parts, relying on sentences to build to a larger narrative.

Like reading, graphicacy is far more than a perceptual task. It, too, leverages semantics to generate meaning. Semantics can incorporate everything from the very tangible choices of color to the broader shape the entire visualization makes (think art composition) to register (degree of formality in an interaction). These parameters can make or break a consumer’s understanding of the visualization.

Charts are more than pictorial representations of data. They are classifier systems that rely on numbers and words to lend them greater meaning. When preserved, they become idioms of the culture and language that created them. Are the two icons below meaningful to you?

Coxcomb chart (ala Nightingale) and spiral chart (Du Bois) in icon format.

Practioners may note the first looks a lot like Florence Nightingale’s Coxcomb or rose chart while the second recalls W. E. B. Du Bois’ spiral graphs. These charts – and others – are part of a tradition steeped in graphicacy.

When cultures are truly literate, it’s not only the individuals that change, but the society. The broadening of graphicacy demands access that includes disability (what Braille and audiobooks have both done for literacy), financial access (libraries, as a starting point) and education. It requires concerted effort in teaching beyond the literal words of the trade, but distillation of the greater system that makes a chart. It also requires us – the data elites – to get out of the way and empower others. We can choose to be Socrates – who didn’t set much in store by writing – or follow the example of King Sejong, either the creator or instigator of Hangul.

It’s our mark to make.

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