Even today modern-day economists: Between 1995 and 1998, I presented the following toy puzzle to hundreds of econometrics students and faculty across the United States:

Consider the classical supply-and-demand equations that every economics student solves in Economics 101.

1. What is the expected value of the demand Q if the price is reported to be P = p0?

2. What is the expected value of the demand Q if the price is set to P = p0?

3. Given that the current price is P = p0, what would the expected value of the demand Q be if we were to set the price at P = p1?

The reader should recognize these queries as coming from the three levels of the Ladder of Causation: predictions, actions, and counterfactuals. As I expected, respondents had no trouble answering question 1, one person (a distinguished professor) was able to solve question 2, and nobody managed to answer question 3.

The Model Penal Code expresses: This is a set of standard legal principles proposed by the American Law Institute in 1962 to bring uniformity to the various state legal codes. It does not have full legal force in any state, but according to Wikipedia, as of 2016, more than two-thirds of the states have enacted parts of the Model Penal Code.

Заметки к главе девятой

Заметки к главе девятой

Those sailors who had eaten: The reason is that polar bear livers do contain vitamin C.

“On the Inadequacy of the Partial”: The title refers to partial correlation, a standard method of controlling for a confounder that we discussed in Chapter 7.

Here is how to define the NIE: In the original delivery room, NIE was expressed using nested subscripts, as in Y(0,M). I hope the reader will find the mixture of counterfactual subscripts and do-operators above more transparent.

In that year researchers identified: To be technically correct it should be called a “single nucleotide polymorphism,” or SNP. It is a single letter in the genetic code, while a gene is more like a word or a sentence. However, in order not to burden the reader with unfamiliar terminology, I will simply refer to it as a gene.