Representing Data - Data Points: Visualization That Means Something - page 99

a lot by stretching out the scale. Likewise, you can make a big change look
like a little by compressing the scale.
A rule of thumb is to scale your visualization so that direction fluctuates mostly
around 45 degrees, but this is hardly a concrete rule. The best thing to do is
to start with this suggestion and then adjust accordingly based on context. If
a small change is significant, then it might be appropriate to stretch the scale
so that you can see the shift. In contrast, if a small change is not significant,
don't stretch out the scale just to make a shift look dramatic.
FIGURE 3-7 Slope and time series