The chart is part of the argument
A statistical graphic does not merely display data. Axis origin, range, aspect ratio and labelling influence how strongly viewers perceive change.
The historical example on population growth in China illustrated this point: the same dataset can appear dramatic or comparatively restrained depending on the scaling of the vertical axis.
Core lesson: A truncated or tightly cropped y-axis can visually magnify differences. A wider scale can make the identical development appear far less spectacular.
Why this matters
The underlying numbers need not be false. The visual presentation alone can mislead. When judging a chart, ask at least:
- Does the y-axis start at zero, and if not, is the truncation made obvious?
- Is the displayed range justified by the subject matter?
- Do equal visual distances represent equal numerical distances?
- Would another plausible scale create a substantially different impression?
A durable teaching example
The old Klein-Singen URL continued to be cited in university teaching material years later as an example of a misleading graphic. The historical URL therefore remains preserved through a permanent redirect to this reconstructed page.
The broader lesson is timeless: when reading statistical graphics, inspect not only the data but also the visual grammar used to present them.