Summary chart with 3 completely different data ranges

Sometimes you want to show 3 data sets in one chart with very different data ranges, for example:

1,000s of customers
$ sticker price per unit
Number of products bought per customer

One solution:

Set the column of the first data point of each series to 100
Calculate the 2nd value relative to the 100
Manually paste data labels with the correct factors

The chart below gives an example:

The first chart contains the unadjusted data
The second chart shows the adjusted version
The third charts shows the values I have entered in the PPT columns

Click on the example image below for a larger image.

3 comments

Mike Pulsifer2009-04-13 16:16:00

Got to be careful. You don't want to sacrifice the integrity of the data or look like you're playing games with the interpretation of the data. Like it or not, the heights and perceived values therein of the three graphs will be compared to each other by the audience, whether they're adjusted as you describe or arranged as you show in the 3rd panel.

If the audience feels that you're trying to pull a fast one on them, even if you're not, the rest of your presentation will lose its believability.

Jan Schultink2009-04-13 17:10:00

Hi Mike,

No fast ones here.

10,000 customers, $13 sticker price per unit and 20 products per customer are just completely different metrics. I try to show the trend in each of them.

The minimalist mathematical approach would have been to show 3 bars: % change in each of the categories. This would have a bit too abstract for me though.

Chrislbs2009-04-14 14:33:00

I read this as communicating two different ideas. If the main comparison is the relative value of 1,2,3 compared to the high value, then just show that (a la panel 3). If the absolute levels (high and low across the factors) are of interest then put that in a table.

My brain wants to compare things across in the same chart, and 1000's of customers and the number of items each buys are quite different.