Yesterday I read about interaction plots on junk charts where he points out the merits of an interaction plot. Interaction plots show interaction effects between 2 factors. For eg. you can show how your product sales have changed between year 1 and year 2 using an interaction plot like below:

As you can see, interaction plot is a simple line chart with several series. You can easily make this in Excel. Here is a simplified tutorial to help you get started.
Step 1: Select the data and insert a line chart
This is simple, just insert a line chart from the data.
Step 2: Go to the line chart “data” and change rows to columns
You require this step only if your data is oriented differently.

Step 3: Format the interaction chart
Since excel colors each line series differently, you need to change the colors, add labels, adjust the label source (from data to series) and then format grid lines etc.
That is all, your interaction plot is ready to go.
Download interaction plot template for excel and play with it
Click here to download the interaction chart template for excel and use it to make your own interaction plots.
Points to consider when you are making interaction plots,
- Interaction plots can be too messy if you have a lot of series. Generally they loose the appeal after 6-7 series of data.
- Chart formatting with more series of data can be a pain too. Use F4 key if you are found repeating same steps.
- Make sure you don’t color individual series differently. You can use same color and label instead. It looks a lot better that way.
- In cases like last year vs. this year or budget vs. actual, you can even use clustered bars. See more examples on budget vs. actual charts for inspiration.
What is your opinion about interaction plots?
I think they are good for small data samples. I have personally not used them, but I like the idea and will use them when there is an an opportunity. What about you? Have you used them in any professional setting? How did your audience feel about the chart? Tell us using the comments.

















9 Responses to “Show forecast values in a different color with this simple trick [charting]”
While this works in a pinch, it clearly "lightens" the colors of the entire chart. Depending on where you use this, it will be blatantly obvious that you don't know what you are doing and present a poor looking graph.
Why not separate the data into different segments when charting and have as many colors as you have data points? You might have to create a new legend and/or repeat the chart in "invisible ink", but it would be cleaner and more consistent when new or updated data becomes available.
While I think I agree that doing it "properly" via a second series is preferable, I don't necessarily agree that making the entirety of the "future" (data, gridlines, and even the axis) semi-transparent is "poor looking". I think it could be seen as adding more emphasis to the "future-ness" of the forecast data.
In short, it's another tool for the toolbox, even if it's never needed.
Simply and clever 🙂
Quick & effective, cool. thanks.
I always use the dummy series.
Nice little trick, thanks very much!
Two sets of data better. Control is much better.
You can use the same chart next month to see what is actual and what is forecast.
To use this trick, I think grid lines has to be removed, that will make the graphic much more sharp.
to be honest, i dont understand why there is needed to do this way... in this case horizontal lines will be pale as well. then why a just can't change the color of the line partly???
Great tutorial. Thanks for the tutorial!