A comet chart is a type of visualization used to display the trajectory of data points over time. 

They’re often used to compare one time period to another to see the direction of the change.

The tail starts at the first time period and grows like a comet to the second period.

I don't believe in complexity in data visualization. I stick with simple charts when you needs to compare measures to add context.

Tableau workbook here.

How many people power the Forbes Cloud 100? Is there a correlation between company rank and employee size? Have they expanded or contracted.

Learn how to build 28 charts in 60 minutes that compare two years.

In this session I first reviewed the original visualization, then went into data discovery and analysis before finishing with a new visualization.  Watch the video and interaction with the visualization below.