How to detect outliers in trending time series dataset?


New Member
Boxplot can be used to identify outliers, but if the baseline is shifting upwards, the result is biased. Thus, I am wondering how to detect outliers in such a scenario? Thanks in advance.

Ken Abbott

Managing Director
You can screen for +/- 2 std, etc, but there is no substitute for visual inspection. At Morgan Stanley, we looked at 25,000+ time series every time we updated the data. There may be an AI/ML solution, but a) I haven’t seen one and b) I wouldn’t want to bet my career on it.