Bubble charts

[KG]

A colleague of mine was asking me to use a bubble chart to show the following
data for 2004, 2005, 2006 and 2007:

Sales Dollars
Margin Dollars
Margin as % of sales

I couldn't think of a way to display all these data on a bubble chart and
recommended a combination bar/line chart instead, with the margin % shown as
a line with its own Y2 axis.

Was I wrong and can the above data set be displayed on a bubble chart after
all?

 

[Jon Peltier]

The data can be displayed on a bubble chart. However, one of the harder
things for people to do is correlate the size of a bubble with a value. A
combination bar-line or a line on two axes chart is a better choice.

- Jon

 

[KG]

Jon, suitability of a bubble chart aside: how can I even show 4 years of
sales $, margin $ and Margin $ on the same bubble chart?

 

[Jon Peltier]

Actually, that's one more variable than fits, if year is across the bottom
axis. I was writing something quick before dinner got cold.

- Jon

 

[KG]

Thanks Jon, I just wanted to be certain that I didn't misspeak when I told my
colleague that this data set would not fit into a single bubble chart.

 

[Andy Pope]

If you were going to use a bubble would it not be

Years as series
Sales Dollars on x or y
Margin Dollars on y or x
Margin as % of sales bubble size

This assumes a single value/bubble for each year.

Cheers
Andy

 

[Jon Peltier]

Andy -

It would work this way, and that might be what I was thinking, but most
times the chart only makes sense with years across X.

- Jon

 

[David F Cox]

It is almost certainly not worth the effort, but you could have a bubble
representing margin inside a bubble representing sales and use colouring to
represent the percentage. This sort of chart impresses people with your
knowledge without imparting much of it.

 

[Jon Peltier]

... without imparting much of it.

LOL

- Jon