Start with two values: Store A is 42 and Store B is 45.
Before judging the gap, read the value axis. This chart runs from 40 to 46, with tick labels at 40, 42, 44, and 46.
The exact difference is 45 - 42 = 3. Say 3 units higher; do not let the zoomed axis decide that the difference is automatically big.
A tiny chart-reading step: read the axis range before deciding whether a difference is big.
highlighted = computed this step
Start with two values
Start with 2 pinned values.
pinned values
Read the axis range
Read the value-axis range before judging the visual gap.
axis range first
Read values on that scale
Place both values on the chosen value scale.
values on scale
State the bounded difference
Readout: Store B is 3 units higher than Store A, not automatically big.