I am trying to create a control chart for metrics that are essentially increasing over time. If I attempt to create a Shewhart chart, there will be many points that are above the upper specification limit.
So for example,
My metric is Revenue. Since it is a fast growing company, Revenue is going to be increasing over the specification limit over time. The main thing I want to track is when it is below the lower specification limit.
I know this is very vague but essentially I want to create a control chart that has data increasing over time.
plot() is your game here. Time on the X, revenue on the Y with an
abline(h= ) for your specification limit. Set a horizontal line where your specification limit is and you are good to go.