Specifying custom changepoint locations
James Rodríguez is a Colombian soccer player who played in both the 2014 and 2018 World Cups. He was a standout player in both World Cups but won the Golden Boot award in 2014 for scoring more goals than any other player in the competition. I chose his account because it exhibits some very interesting behavior that would be extremely difficult to model without changepoints:
Figure 8.10 – James Rodríguez’s Instagram likes per day
The number of likes his Instagram posts get is gradually increasing over time, but there have been two notable spikes, in the summers of 2014 and 2018 when he was playing in the World Cup. It is clear that the spike in 2014 resulted in a significant trend change. The number of likes that his posts were getting increased dramatically during the World Cup and dropped afterward, but not to the same baseline as before. He gained a large number of new followers during this...
