Truncating a Time-Series Graph

Question

I'm looking for a way to truncate outliers in a time-series graph.

Some context: I'm plotting two different metrics on a single graph. It's important to understand what portion of "Metric A" takes up respective to "Metric B". "Metric B" can at times spike to a high value thus increasing the Y-Axis scale which then minimizes the visibility of Metric "A".

Are there any good formulas that help normalize this data or visual treatments that can make the graphic honest as well as accessible?

See screenshot for more context. The blue area is "Metric B".

Thanks!

Answer 1

If Metric B spikes up too much (say to more than twice the maximum of Metric A), you can display it as a vertical blue column with a jagged break in the middle to indicated it goes off the top of the graph. I have also seen it with a jagged break and an arrow on the top. You can also list the specific data point to show how tall the spike is.