How much change has occurred?

A relatively straightforward challenge was set by Luke this week, to visualise the difference in Sales between 2020 and 2021 in a slightly different format than what you might usually think of.

Start by filtering the data to just the years 2020 and 2021 (add Order Date to the Filter shelf and select specific years, or add a data source filter to limit the whole data set).

Add Sub-Category to Rows, and Sales to Columns, then add Order Date to Colour which by default will display as YEAR(Order Date). Colour the years appropriately.

Now unstack the marks (Analysis menu -> Stack Marks -> Off), and re-order the colour legend, so 2021 is listed first (this makes the 2021 bars sit ‘on top’ of 2020).

Adjust the size to make the bars thinner.

Now add another instance of Sales to the Columns shelf, and make the chart dual axis (synchronising the axis). Reset the mark type of the original SUM(Sales) marks card back to bar.

We need the circle mark for the 2021 Sales to be blue. To do this, duplicate the Order Date field, then add Order Date (copy) to the Colour shelf of the SUM(Sales)(2) marks card. This will show another colour legend, and you can set the colours accordingly. Add a white border around the circle marks.

To work out the % difference to display on the label, we need the following fields

2021 Sales

{FIXED [Sub-Category]: SUM(IF YEAR([Order Date])=2021 Then [Sales] END)}

This returns the value of the 2021 sales for each Sub-Category against all the years in the data set. Similarly we need

2020 Sales

{FIXED [Sub-Category]: SUM(IF YEAR([Order Date])=2020 Then [Sales] END)}

which means we can then create

% Difference

(SUM([2021 Sales])-SUM([2020 Sales]))/SUM([2020 Sales])

format this using custom formatting to display as +0%;-0%

Now we can add % Difference to the Label field of the Sum(Sales)(2) marks card.

You’ll notice you’ll have duplicate labels displayed. To resolve this, you need to adjust the label settings as below

To sort the rows, you need to sort the Sub-Category field by 2021 Sales descending

And finally to show the value of the 2021 Sales, add this field to the Rows shelf, and change to be discrete (blue pill).

All that’s left to do now is adjust the wording of the tooltips as you see fit, and format to remove gridlines, headers etc.

My published version is here.

Happy vizzin’! Stay Safe!



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