This week, we’re going to continue thinking about non-experimental study design, focusing on how researchers build a case for their results being (a) causal, and (b) not spurious.

Discuss the following questions as a group. Professor Rao will visit each group to help clarify any questions you may have. We’re going to try something a bit different this time: rather than having a longer small-group discussion period and a short full-class discussion period, we’re going to do a random seminar for the big group time. To give you more time to read the article and formulate your own questions/thoughts, there are fewer questions than usual in the exercise here.

Random seminar

Each of you will be selected randomly, without replacement, to share your thoughts/questions from your small-group discussions for 2 minutes. You can use your time to share your thoughts and questions, respond to others, or both.

When your time is up, the alert will flash, and Professor Rao will say it’s time to move on. If we finish with time to spare, we can have a less-formal chat. You can skip your turn if you’d like by saying “skip”, and you can also finish early if you’d like.

How did the Voting Rights Act affect economic inequality?

Here’s the article: Voting rights equal economic progress: The Voting Rights Act and U.S. economic inequality

1. The key result
  1. What is the key comparison (or comparisons) the authors use to tease out the effect of the VRA on economic inequality?
  2. Is there an experiment they could have run instead?
  3. What is the main result?
2. Confounders
  1. What are the key confounding variables the authors worry about?
  2. Do you see any others which aren’t mentioned?
3. The story
  1. What are the mechanisms the authors point to as explanations of how their results might have come about?
  2. Do you find the mechanisms plausible?
  3. Are there other mechanisms you might find plausible?
4. Your questions/thoughts
  1. What do you think of the article? What questions are you left with?