Thank you! I know that you will find a lot of errors in this sequence, so please point them out whenever you see them.

The reason for the superscript is that this was originally written for students in the epidemiology department at HSPH, where superscript is the standard notation due to Prof Hernan's book. I didn't want to change all the notation for the Less Wrong adaptation..

I am currently on my phone and will fix the definition of a confounder later tonight when I have access to a real computer. It is probably too early to give a definition before I introduce graphs

Edited to add: The simplest DAG where the definition in the first sentence of Wikipedia fails is when the suspected confounder is a mediator. I think the simplest example where the second definition on Wikipedia fails is M-bias. I will cover M-Bias in Part 3 of the sequence