Visualizing with Clarity - Data Points: Visualization That Means Something - page 239

Warning: Make sure your data is comparable
when you transform multiple datasets. Are they
from the same source? Is the methodology the
same? What level of uncertainty is attached to
the estimates? If you're not sure, you should
find out because incorrect math can lead to
incorrect conclusions.

Of course, as you saw in Chapter 2, visualization as a medium
creates a wide spectrum of applications. How much you
highlight, how much you explain to viewers and readers,
and what you display depends on what you want to show
and who you present to.

FIGURE 5-42 Cumulative values and totals