Discussion..
Difference-in-difference
Rarely do business researchers get the luxury of conducting controlled experiments with thousands (or more) participants. Instead, we must search for experiments that have occurred naturally "in the wild". For example, attached below is an example of a difference-in-differences (DID) study, published in JAMA Pediatrics. In it, the authors evaluate the impact that legislation has had on adolescent suicide rates using DID.
DID is frequently used to evaluate program initiatives, government policies, and the effects of natural disasters. To provide more clarity, I've included links to two videos below. The first one is a hypothetical policy evaluation from the European Union Joint Research Centre, and the second is a slightly more technical explanation looking at a hypothetical school program initiative.
EU DID - https://www.youtube.com/watch?v=IpWQlHapifU&feature=youtu.be (go to this video with this link)
School Lunch Example - https://www.youtube.com/watch?v=XFqFH97bDy4&feature=youtu.be (go to this video)
The primary strength of using the DID method is that it is relatively simple, yet still statistically powerful. The trick is finding a natural experiment to evaluate. For this discussion, each of you should come up with an actual idea for a DID study. You need to find a "treatment" to evaluate (new policy, natural disaster, etc.), your two sources of variation (e.g. time & schools in the second video), and identify (with hyperlink) the data to use for the evaluation.