What is a Pareto Chart?
A pareto chart is a useful tool to analyze the contribution of causes to a result. In other words, we can analyze in a single chart for example how many products or categories contributed to my amount of sales. The pareto law states that usually 80% of your sales come from only 20% of your products. This saying can be used and analyzed in a lot more ways than just sales.
Building a Pareto Chart in Tableau
On today’s blog I’ll show how to build a Pareto chart in Tableau and see if this rule is accurate. I will use my Sales as the Measure and the Product Name Dimension.
We will be using the Superstore handy dataset to build our chart, but you can use your own dataset to build it.
First step is to add your data to your worksheet.
Drag your Sales to rows and Product Name to columns. We will then change the Product Name to make it a Count (Distinct) so every product appears only once, and we can use it to create a Table Calculation.
Drag your Product Name from your Dimension into your Marks card and don’t forget to make it a Line Chart.
Now we can create our Table Calculations.
First, we need to make a Running Total of the Sales along our Product Name. We will also need to make a Percent of Total in a Secondary Calculation, to see how much our % of sales at each point has been. Use your Product Name as the Specific Dimension to make sure that your sales are calculated along them.
Second step is to use Table Calculations for your Products Name so they show us the Running Total for each of them and we will also need to add a Secondary Calculation to see the percentage of total.
We will Compute Using our Product Name in the Running Total SUM, and in the Percent of Total we could use Table Across but we will need to sort it later, so again use Specific Dimension and choose your Product Name.
Now we have all our calculations created but we just need to Sort them to make the line chart. Custom sort both measures and your Table calculations using your SUM of Sales in descending order.
We now have our line chart finished but we could add a reference line to see if the pareto law is true, so create 2 reference lines. The one for the sales should have a constant value of 80% and the Products one with 20%.
Format the chart as per your preference including the titles of the axis, also format the Tooltip so when someone hovers over each value they understand what they are looking to.
Our chart shows that more than 22% of the products make up to 80% of the sales. Try with your own dataset and analyze your results.