A Series of Statistical Charts Illustrating the Condition of the Descendants of Former African Slaves - Circle graph shows comparison of African Americans in various occupations to whites [LCCN2013650371]
The pattern
This still is filed under Data as proof.
Define
A chart, map, or count that is the argument, not an illustration next to the argument.
Mechanism
Sighted evidence. The reader is asked to believe their eyes: a bar, a share, a spread on a map.
Verdict
The claim is comparative or quantitative and the figure can be read without a caption doing the sell.
Why it works
The chart is six comparisons forced into one shape, all sharing a common centre and a common radius, so the reader compares sliver widths without any axis, scale or number. Colour does the entire argument: solid black against hatched grey needs no legend, and the eye finds the two fat black wedges in under a second. Putting an ALL OCCUPATIONS arc in the same ring gives a built-in benchmark, so each sector is read as above or below the national norm rather than in isolation. Setting the labels along the curve outside the ring keeps the data field completely clean.
Steal this when
When you have one ratio measured across five or six segments and want the outliers found instantly rather than looked up. Put every segment in one shared frame, include the overall average as one of the segments, and let contrast carry it with no numbers on the artwork.