Tableau Control Chart - Attribute measure incorrect

Question

All

I have a control chart, with on the X-axis a time period, and the Y-axis the value of the measure (I'd like to plot all the points in a control chart).

However, I have 2 different values as a measure, which have the exact same date (up to a second match) but different measure values.

When I plot this on a control chart, instead of having 2 points in the control chart with value 500 and 550 for example - it gives me one point with a value of about 200. It also gives a notification that there is a NULL value in this axis, which points to the X-axis where 2 records have the exact same date.

Any idea what I can do to make this correct - or make tableau draw the measure points correctly?

Thanks in advance!

Answer 1

It's difficult to answer without seeing more detail about your problem, but this sounds like a good candidate for a blended axis. (multiple measures sharing a single axis)

The easiest way to do this is to put your (probably continuous) datetime field on the row axis and one of your measures on the row axis to see one of then control plots. Then drag the second measure to the Y-axis until you see a little translucent two bar icon to indicate that you are adding a second measure to that axis, at which point you can release the pointer and you should see a two plots on the same axis.

If the scales for the two measures are radically different, you can instead drag the second measure to the right side instead to get a dual axis.