line graph, slope graph

A slopegraph is a lot like a line graph, in that it plots change between points however, a slopegraph plots the change between only two points, without any kind of regard for the points in between.

It is based on the idea that humans are fairly good at interpreting changes in direction. Decreases and quickly rising increases are easily detected.

Slopegraphs are often used to show change over time but have also been used to compare two groups, such as boys and girls.


Beginning of school year performance compared to end of year

Slope graph showing performance of six schools from the start of the year to the end: while most schools increased, only one school met growth targets and one school decreased

In this example, the slope graph compares school performance at the beginning of the year (BOY) to the end of the year (EOY).

Source: Stephanie Evergreen

Advice for choosing this method

Choose this method when you want the audience to focus strictly on the beginning and endpoints. If, for example, a traditional line graph would reveal significant variations in the data, a slopegraph would not be the best choice because it masks any data points in the middle.

Advice for using this method

Though it might seem redundant, it’s helpful to label both points with the full category name and value. Otherwise, it can be tricky to follow the line, especially if the lines cross. Colour coding lines of interest and matching the label colour can also help draw out a story in a dataset.




Other ways to visualise changes over time

'Slopegraph' is referenced in: