The Georgia Negro: A Social Study - Bar graph shows the amount of land owned by African Americans in Georgia from 1874 to 1899 [LCCN2013650438]
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
Labelling only the first and last bar is the discipline that makes the plate work - the reader is given a start, an end and twenty-three uninterrupted steps of evidence in between, with nothing to read and no arithmetic to do. Stacking the bars with almost no gap converts twenty-five discrete comparisons into a single silhouette, so growth is perceived as a shape rather than counted. Plotting every single year, including the flat ones near the end, is what buys the credibility: a chart that only showed 1874 and 1899 would be a claim, and this one is a record.
Steal this when
When you need to show sustained progress over many periods and a start-and-end comparison would read as cherry-picking. Plot every period, label only the two endpoints, leave the plateaus visible, and let the silhouette carry the argument.