Do you need to display or link to non-quantitative metadata? (including captions, labels, etc.)

More often than not, there is good reason to show some ‘data about the data’ (metadata) with the visualization. For example, the data source, the sampling process, whether/how and by whom the data was (pre)processed, who created the visualization, time information  (when was the data collected, when was the visualization created), if there are legal or proprietary restrictions, or practices that allow discovery and identification (e.g., labels/tags/keywords, a title). Such metadata is very important, there are even standards about them! Metadata can ‘make or break’ the proper comprehension and contextualization of a visualization.

So, what should we show and how should we exactly show it? In principle, all critical information should be included, and if there is any chance that you’d mislead the viewer if this piece of information was not available to them; the information must be shown and the viewer should be guided to it.

Example: Metadata for environmental observations (map)
The example below includes useful metadata for its audience, all shown as text (Allan et al., 2015)

Last revised: 12th of July 2018, Arzu Çöltekin