The four questions about graphs are (1) whether, (2) where, (3) how, and (4) which.
Yes, yes, yes. Use as many as you sensibly can. Well-drawn graphs are tremendous attention grabbers and are more effective than many pages of prose in making a point. Look at any issue of Bloomberg Businessweek to see how graphs can make a smashing headline for an article. You’ll find things like this:
Wiftandia’s Balance of Payments Is Improving Dramatically
Having seen only this much (12 square inches, 30 seconds) you already have a clear outline of the whole subject.
First of all, a graph ...