Context involves both the background for the data and how the data behave. This behavior of the data is most easily seen by using two complementary graphs—the running record and the histogram. Here I address the secrets of creating useful histograms.

The first graph mentioned above—the running record or time series—is incorporated into the XmR chart. The virtue of this graph is that nothing can hide—each value has to sink or swim on its own. By showing how the values vary over time, the time series graph draws our eyes in the direction our minds want to go. In this way the running record is like a movie of the data.

In contrast, the histogram of the data is like a group photo of the whole family. Here we see how each value compares with all the related values. But a family photo is not very good if some people are not looking at the camera, and others are hidden by those in front. So how do we sharpen up our family photo?

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