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.
Bring the idea into a day.
Imagine two charts covering different time spans. Their slopes cannot be interpreted fairly without reading the horizontal axes first.
Another angle on the story.
Look for the comparison behind the visual impression. The baseline, time window, and group definition can change what a pattern seems to mean.
- Read units and scale first.
- Check the range being shown.
- Compare the visual impression with the actual difference.
Follow a related question
Define the reviewer’s responsibility.
Human review needs a specific jobCompare one object under two light sources.
A color depends on the lightKeep learning
Related background to continue exploring this subject.
NIST: statistical engineering W3C: accessibility, usability, and inclusion