When we want to show the impact of a proposed change, one of the ways we can do it is to show a line graph of the current state and the proposed state with a shaded area between the two to emphasize the difference. This is much better than the default table of values that we see in too many presentations.
Here’s an example of showing the difference between the base case for revenue and the revenue if we introduce a new product.
You don’t need any fancy software to create this type of meaningful visual. There are a number of different ways to create this graph in Excel or PowerPoint. The method I discovered is simple to use and works in many different scenarios.
The current state and projected lines are straightforward. The shaded area between the lines is created using a stacked area graph with two series. The first series in invisible and is the same as the current state line. The second series is the difference between the two lines and is the shaded area. If you want the gridlines to still be visible, you can make the shading color semi-transparent (I find 50% works well).
I’ve created a video tutorial to show how this method works in Excel and how it applies when the difference is positive in some time periods and negative in other time periods, such as this example.
You can view the video below.
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There are other methods for creating the shaded area that may work better for more complicated situations. Two Microsoft MVPs have written tutorials that you should refer to if you have a more complex situation. Excel chart expert Jon Peltier’s solution is here and Excel expert Chandoo’s solution is here.
When you want to show the difference a change will make to future results, consider adding a shaded area between the two lines representing the current state and projected state to emphasize the difference.