Testing Instrumental Variables Assumptions (The Effect, Videos on Causality, Ep 60)

Please visit https://www.theeffectbook.net to read The Effect online for free, or find links to purchase a physical copy or ebook. The Effect is a book about research design and causal inference. How can we use data to learn about the world? How can we answer questions about whether X causes Y even if we can't run a randomized experiment? The book covers these things and plenty more. These videos are meant to accompany the book, although they can also be viewed on their own. This video relates to material found in Chapter 19 of the book. A version of this video without background music can be found here: https://youtu.be/CXJo1phMyzc Instrumental variables is chock-full of assumptions that all need to go right or the thing will fall apart! Are there any ways we can use the data to check whether these assumptions are likely to be true?