Setting the Purpose and Identifying Key Factors - Data Visualization: A Successful Design Process - page 34

So how can we rationalize the role of these two very different, opposing perspectives
and beliefs? In my view, the latter enhance the field by demonstrating what can
be achieved through the aesthetic and technological creativity. The former help us
understand what we should do through the pursuit of evidence and observation of
rules around human cognition and visual perception. We need visualizations that
look appealing and we need visualizations that perform well.
However, sometimes there has to be mutual recognition that for different scenarios
there might be good reason for leaning more towards one direction than the other.
Let's look at the language of two potential motives behind creating a data visualization:
• "We need a chart to help monitor…"
• "We need to present this in a way that persuades people…"
Here, we have two situations both aiming to better inform a reader or a user, but the
intended effect or outcome from the experience will be different.
The reaction of a user reading, for example, a dashboard full of bar charts and line
charts to help monitor monthly performance will be quite analytical and pragmatic
in style. It is unlikely to involve or stir much emotion (unless things are suddenly
and unexpectedly plummeting). The style of the visualization design will be
consistent with the intended nature of this particular type of engagement, probably
quite sober and with an emphasis on the precision of perception.
Compare that with the intended impact of a presentation that depicts how many lives
could be saved if a charity was able to achieve a certain level of fundraising. The setting
and intent will be more about persuasion making it emotionally charged. It will need to
attempt to create an experience that is much more personal and more impactive.
Here, we see potentially two ends of a spectrum for judging the right tone. Yet they
fundamentally share the overall motivation of wishing to inform people about a
subject through the visual representation of data.
One scenario would achieve this in a relatively pragmatic style, influenced by a desire
to optimize the efficiency and accuracy of interpretation. The other would be judged as
effective if it evoked a suitably positive emotional response to the data story.
We can therefore describe tone as being a continuum from a pragmatic or analytical
portrayal through to a more emotive or abstract concept.
Pragmatic and analytical
The following is a quotation from Jock Mackinlay ( http://hci.stanford.edu/
courses/cs448b/f10/lectures/CS448B-20100923-DataAndImageModels.pdf ):