Chapter 9: Outliers and Special Events
An outlier is any data point that lies significantly away from the other data points along one or multiple different axes. Outliers may be incorrect data, such as resulting from a miscalibrated sensor producing invalid data, or even a finger slip on the keyboard during data entry, or they may be accurately recorded data that happens to wildly miss historical trends for various reasons, such as if a tornado passed over a wind speed sensor.
These uncharacteristic measurements will sway any statistical or machine learning model, and so correcting outliers is a challenge throughout data science and statistics. Fortunately, Prophet is generally robust to mild outliers. With extreme outliers though, there are two problems Prophet can experience: one problem with seasonality and another with uncertainty intervals.
In this chapter, you'll see examples of both of these problems and learn how to alleviate their effects on your forecast. You...
