Rule number one in Data School is that if Andy teaches you a new trick, you have to blog about it straight away. As a stickler to the rules, here’s my blog about this surprisingly simple chart type.

If you want to follow along, I’m using the 2019 MakeoverMonday W49 data on the effect of union membership on wages.

Step 1

Put your date data into columns as a dimension (blue pill), and your measure into the rows.

Step 2

Turn the mark type to circles, put your dimension into detail and filter out any superfluous dimension members (for this chart type, you can only have two circles).

Step 3

Duplicate your dimension and create a dual-axis and synchronise those axes.

Step 4

Change the second mark type to line and put your dimension into path (this should be the same dimension in your columns section).

Step 5

Play around with the formatting, and you’re done!

Surprisingly easy.