In Dougherty et al. “Sheff v O’Neill: Weak Desegregation Remedies,” the following data is given to show the progress toward the Sheff I goal during in the years 2003-2007.
This table shows the percentages of minority students enrolled in reduced-isolation magnet schools and Project Choice schools in suburban districts.
When plotted on a line chart, the data can show a progression either minor or significant. All depends on how the chart is formed.
This first chart portrays the data in a way that shows minor progress with a relatively flat line. The effect is created by using a large range of percentages along the vertical axis, fixing the minimum at .0 (0%) and the maximum at 1.0 (100%).
In contrast, this chart portrays the data in a way that shows significant progress with a more steeply sloped line. The effect is achieved by using a small range of percentages along the vertical axis, fixing the minimum at .1 (10%) and the maximum at .3 (30%).
Both charts represent the same set of data. However, their difference in showing the progress, either minor or significant, is an example of how charts can be used to lie or otherwise give the reader a false impression of what the data means.