A line can look dramatic or nearly flat depending on the range shown by the chart. Before interpreting the shape, read the axis labels, units, and scale.
Check whether intervals represent equal steps and whether the chart uses a transformed scale. A narrowed range can reveal a small variation, but the reader needs enough context to understand its size. The right presentation depends on the comparison being made.
Ask what the chart would look like under another reasonable range. The purpose is not to require every chart to use the same starting point, but to recognize the choices that affect the visual impression. A useful chart makes those choices legible.
- Read units and scale first.
- Check the range being shown.
- Compare the visual impression with the actual difference.
Imagine a practical setting.
Consider a chart whose vertical scale begins near the observed values. A small difference can occupy much of the drawing without becoming a large absolute change.
Before the next experiment.
Look for the comparison behind the visual impression. The baseline, time window, and group definition can change what a pattern seems to mean.
Follow a related question
Compare one object under two light sources.
A color depends on the lightIdentify which material is actually included.
Context is an input with a boundaryKeep learning
Related background to continue exploring this subject.
NIST: statistical engineering W3C: accessibility, usability, and inclusion
