September 3, 2010

Tableau Tip: Creating a Waterfall Gantt Chart

I keep up with the website eagereyes regularly and recently they ran a three-part series titled "A Protovis Primer" in which they introduced the tool Protovis. Protovis is an open-source tool that allows you to create data visualizations.

Part 3 of the series was dedicated to instructions for creating a waterfall chart. If you take a quick look at the tutorial (well, there is no way to read it quickly), you will see that the method they have for creating a simple waterfall chart is in fact quite complicated and requires a lot of coding.

There's a much simpler way to do it...use Tableau. Here's the step by step way to do it create a Gantt chart using the same Presidential data eargeyes used (I added data from different polls that ranks all of the Presidents). Get the data here.

Step 1 - Add Inauguration to the column shelf and # and President to the row shelf. You need to have the # field so that the Presidents are listed in order from Washington to Obama.

Step 2 - Right-click on the YEAR(Inauguration) field and choose "All Values". This is required otherwise the time scale will not allow you to connect the start and end dates.

Step 3 - Right-click on the # field and uncheck "Show Header". This will hide the # column, yet still use it for sorting purposes.

Step 4 - Create a calculated field named Length of Presidency and drop it on the Size shelf (this gives the bar its length)

Step 5 - Create three calculated fields (Life, Time in Office, Age @ Inauguration) and place them on the Level of Detail shelf.

The end result should be a waterfall Gantt chart like this (I removed the grid lines):

That's it! Very simple, especially after you do it a few times.

Going a step farther, I created a "timeline" that highlights the times each political party was in office. Here are all of the settings:

I put it all together in a dashboard. I made the Political Party field a global filter and highlighting is enabled when you click on the color of Political Party on the right. Finally, I published the workbook to Tableau Public.

Give it a shot. Download the Tableau Packaged Workbook.