In this podcast, Seth discusses the three “malpractices” of presenting graphs and charts. We should understand these pitfalls and potential manipulation because it is always a sound idea to know what the graphs and charts are trying to say and why.
Showing someone a graph, a chart, or a poll is an intentional act. We are choosing something to show someone because we want to make a point. Very often, we do this to amplify the intent of a story. At the same time, we often do the presentation and violate three simple rules.
Malpractice number one is that we need to be careful with changing axes or scales when comparing two or more things. We often manipulate the scales to emphasize or exaggerate minor differences when, most of the time, the differences are not significant at all.
Malpractice number two is using various graphic elements to emphasize the points. A three-dimensional volume is different than a two-dimensional area. A two-dimensional area is different from a one-dimensional line. When we use a three-dimensional volume object to illustrate the change of a single axis, it could create a false impression of the impact of the change.
The third malpractice has to do with how we communicate poll results. First, many polls are not sufficiently random for the results to be beneficial. Second, the poll results often describe people’s feelings at the time of the survey, but the same people may act very differently after some time after the poll. We often mistake polls as reality or certainty when they are merely odds.
The takeaway lesson is that when someone presents a graph or chart, we need to understand the fundamental point that person is trying to convey. We need to ask the right questions to know whether the presenters are presenting things fairly or trying to make a point.
When we present the graphs and charts, we should strive to create charts and graphs that are inherently straightforward, honest, accurately constructed, and still illustrate our perspective. One tip on making a chart is to say precisely what the chart is trying to convey, strip away all the extraneous information to get to the underlying truth and present it as clearly as we can.