Small multiples

trellis chart, panel chart, grid chart, lattice chart

Small multiples are an array of graphs on the same scale that are grouped together in a row or grid and are often used to simplify a data display.

For example, when one needs to show 3 variables, a common mistake would be to create a 3D graph, which is often difficult to interpret. A better method would be to create a separate graph for each category of Variable A, which is composed of a data display for Variables B and C. The graphs themselves can take any form, such as bar graphs, line graphs, or even pie charts.

The key is really that the tiny graphs are all on the same scale, meaning their y-axis all have the same maximum and minimum values. Doing so allows a viewer to compare the mini graphs to one another.


Gender comparison by location of program

several pie charts

In this example, gender is graphed by location of program.

Source: Stephanie Evergreen

Advice for choosing this method

Choose small multiples when a single graph is too cluttered or complicated because too many variables need to be displayed. Don’t use this method if the scales would have to be altered.

Advice for using this method

Because the graphs are tiny, they need to be very simplified. Eliminate gridlines, tick marks, and any other clutter that isn’t necessary. In terms of labelling, you can usually get away with labelling the leftmost graph in the series and then skip labelling the rest. If possible, order the array of tiny graphs from greatest to least on one category.


Other ways to compare sets of values

Tufte, E. (1983). The visual display of quantitative information. Cheshire, CN: Graphics Press.

Cleveland, W. (1993). Visualizing data. Summit, NJ: Hobart Press.

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