Articles

In the last edition of R for Engineering, we learned how to draw small multiple plots in R and harness the power of comparison. We went from a busy graph to being able to use ggplot’s faceting functions to create a small multiples plot. If you need a recap, here’s a link to the last edition.

That is to say, nature’s laws are causal; they reveal themselves by comparison and difference, and they operate at every multi-variate space-time point.

– Edward Tufte

Small multiples have many uses in engineering, but the one I personally use them the most for is characterization and diagnosis. In my line of work, which is quality engineering, the ability to diagnose problems in physical systems (both product and machine/process-related) is a critical skill, and I will go as far as to say that diagnosing problems is a critical skill in any engineering discipline.

In this week’s edition, I introduce you to the concept of small multiples, and, more importantly, how to make them in R. This is one of those really low effort-super high return kind of features of R that can make you look like a rock star of data visualization. So, without further ado, let’s jump right into it!

In this week’s edition, we dig into a scenario you’ve probably run across when working in Excel or other software, for example Minitab —at least I have, many times.

Say you have a complete dataset. The data has been collected, and you’re now getting ready to run plot it or run some sort of analysis on it. It should be plug and play, but it ends up not being the case as the data is not formatted in the right way, and you’re not able to run your analysis (it happens pretty frequently if you ask me).