How Charts Lie: Getting Smarter About Visual Information

Visual journalism professor Cairo (The Truthful Art), who has consulted for Google and the Congressional Budget Office, provides a valuable guide to reading charts with a critical and nuanced eye. With the use of such graphics throughout media only increasing, Cairo insists, persuasively, that “just looking at charts, as if they were mere illustrations,” is not enough; “we must learn to read them and interpret them correctly.” After offering a guide to different kinds of charts, Cairo presents the different ways they can mislead, including by using the wrong data or concealing uncertainty. His examples of misleading charts include one from an antiabortion group purporting to show Planned Parenthood’s cancer-screening and prevention services sharply declining while the abortions it provided sharply rose; Cairo patiently explains how the chart concealed and distorted information, such as by “using a different vertical scale for each variable.” By also criticizing staunchly liberal New York Times columnist Paul Krugman for using a chart depicting the annual U.S. murder rate that omits data from more recent years, Cairo even-handedly demonstrates that the misuse of infographics is not confined to one political side. At a time of widespread concern over disinformation in the media, Cairo provides a valuable corrective to the acceptance of numbers, and their visual representation, as having objective truth. (Oct.)