11 The impact of a time-related event
This chapter covers
- Learning to identify when to use Synthetic Controls, Regression Discontinuity Designs or Difference in Differences
- Understanding their assumptions and limitations
- Using those methods to estimate causal effects
In Chapter 1, we used an example of evaluating the impact of a newly designed website. We learned that the best way to make such an evaluation was using A/B tests. However, as we already know, it is not always possible to perform A/B tests. Therefore, in the final chapter, we revisit how to assess the decision impact by comparing the situation before and after without relying on A/B tests. That is, we focus on understanding the impact of time-related events.
In this chapter, we’ll explore three techniques for estimating the impact of a decision. Each technique works for a different situation. We’ll stick to the following example as our guide in this chapter. As we explore each technique, we’ll modify this example accordingly to understand when the technique works, what assumptions it has, and how to use it to estimate the ATE.