How do I edit the confidence band width for a linear regression in Tableau

Question

I created a plot in Tableau with a line of best fit using the "Trend Line" feature under "Analytics". This plots a line of best fit, with optional confidence bands around that line.

Here's a screenshot of my plot

My question is: how do I edit how wide or narrow the confidence bands around the line of best fit are? I read somewhere that they default to 90% or 95% confidence. I want to be able to widen or narrow those lines by increasing or decreasing the confidence. My goal is to make the bands more narrow.

I couldn't find how to do this online after a lot of searching. Any help is much appreciated!

Thank you

Answer 1

The confidence band for trend-lines cannot be altered in the same way they can be for other trending analytics (such as forecasting). In fact, within Tableau trend-line confidence bands cannot be altered at all.

In order to make the bands more narrow you would need to find a better fitting trend-line. To do this you can right click on the trend-line and click edit and play around with logarithmic, exponential & polynomial options.

I believe that the trendline confidence bands in Tableau cannot be altered because it represents the potential error as calculated from the StdError. This is the deviation around the trend-line from actual data points and is unrelated to confidence %s.

You can see this by right clicking on the trend line in Tableau and clicking 'Describe Trend Line'. This will open a dialogue which describes the derivation of the trend-line. What you will find is the Confidence interval will be drawn the width of the StdError.