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.
Don't
The number is decorative, or the chart needs a paragraph to explain why it matters. Decoration is not proof.
Rights-cleared examples
'By Paying Us Your Pennies' - The Wonderground Map of London Town
A Series of Statistical Charts Illustrating the Condition of the Descendants of Former African Slaves - Bar graph shows African American population between 1750 and 1890 [LCCN2013650366]
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]
A Series of Statistical Charts Illustrating the Condition of the Descendants of Former African Slaves - Diagram shows number of African American almshouse residents [LCCN2014645375]
A Series of Statistical Charts Illustrating the Condition of the Descendants of Former African Slaves - Diagram shows relative number of African Americans in various businesses [LCCN2014645363]
A Series of Statistical Charts Illustrating the Condition of the Descendants of Former African Slaves - Diagram shows value of property owned by African Americans in Virginia, North Carolina, and Georgia [LCCN2014645361]
A Series of Statistical Charts Illustrating the Condition of the Descendants of Former African Slaves - Line graph shows comparison of African American to white populations between 1790 and 1890 [LCCN2013650372]
A Series of Statistical Charts Illustrating the Condition of the Descendants of Former African Slaves - Map shows African American population distribution and circle graph shows professions of Atlanta University graduates [LCCN2005676836]
A Series of Statistical Charts Illustrating the Condition of the Descendants of Former African Slaves - Maps show comparison of African American population in the United States with several European countries and Australia [LCCN2013650368]
A Series of Statistical Charts Illustrating the Condition of the Descendants of Former African Slaves - Maps show percentages of African Americans in the United States between 1800 and 1890 [LCCN2013650369]
Album de Statistique Graphique - Acceleration des Traversees Maritimes. (Acceleration of Maritime Crossings.) [12526.038]
Album de Statistique Graphique - Acceleration des Voyages en France Depuis 200 ans. Baisse de Prix des Voyages en France Depuis 1798. (I. Acceleration of the voyages in France over the past 200 years II. Lower price of the voyages in France since 1798.) [12519.016]