What is a slopegraph?

A slopegraph is a table-like visualization. It is simple, yet it communicates complex information. Typically, the chart tells a before and after story. Across the axis, the chart compares numbers over time. Reading the chart vertically on either side, it ranks a discrete variable.

The chart is revealing ranking, magnitude, and changes over time. The slopes indicate unusual patterns. The chart also goes by the name parallel coordinates. According to Edward Tufte, bumps charts can also be considered slopegraphs.

A brief history of the slopegraph

Edward Tufte, in his 1983 book The Visual Display of Quantitative Information, first showed a “table-graphic [that] organizes data for viewing in several directions.” Since then, slopegraphs become widely popular among data visualization experts for their rather simple, yet elegant design and their ability to carry a lot of information.

Best uses for a slopegraph

• compare values for many categories over two points in time
• display complex information hierarchically
• slopegraphs focus on changes

Slopegraph maker: key features

• change the color of the lines depending on their slope
• show or hide axis labels and values on either side
• adjust line width for all slopes simultaneously or individually
• show or hide grid and axis lines
• indicate line ends with a dot

Resources

• Step-by-step tutorial

Slopegraph: What's new?