Chapter 22: Creating Sparkline Graphics
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FIGURE 22.8
The bottom group of Sparklines shows the effect of using the same axis minimum and maxi-
mum values for all Sparklines in a group.
For the Sparkline group at the bottom (which uses the same data), we changed the vertical
axis minimum and maximum to use the Same for All Sparklines setting. With these settings
in effect, the magnitude of the values across the products is apparent, but the trend across
the months within a product is not.
The axis scaling option that you choose depends upon what aspect of the data you want to
emphasize.
Faking a reference line
One useful feature that’s missing in the Excel implementation of Sparklines is a reference
line. For example, it might be useful to show performance relative to a goal. If the goal is
displayed as a reference line in a Sparkline, the viewer can quickly see whether the perfor-
mance for a period exceeded the goal.
You can, however, transform the data and then use a Sparkline axis as a fake reference line.
Figure 22.9 shows an example. Students have a monthly reading goal of 500 pages. The range
of data shows the actual pages read, with Sparklines in column H. The Sparklines show the
six-month page data, but it’s impossible to tell who exceeded the goal and when they did it.