The Art and Science of Cause and Effect. Adapted from a lecture by Judea Pearl available on his WEB site: http://singapore.cs.ucla.edu/LECTURE/lecture_sec1.htm. In the ancient world, causal agents were people or animals or deities. . The serpent made me do it.
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Adapted from a lecture by
available on his WEB site:
The serpent made me do it...
Hooke’s law (1678)
Scottish philosopher David Hume argued that the same principle could be applied to human affairs
If we blow up the lab, something was wrong with our model. inferred causal relationships
An example of a multiple regression analysis displayed as a pathdagram. By David Garson.
Econometrics is a term for complex statistical modeling done by economists. It is very complex and mathematical but it doesn’t work well on sociological problems - see my paper on “Myths of Murder and Multiple Regression.”
”If variations like unemployment, income inequality, likelihood of apprehension and willingness to use the death penalty are accounted for, the death penalty shows a significant deterring effect." Isaac Ehrlich, New York Times, 2000
"All of the scientifically valid statistical studies—those that examine a period of years, and control for national trends—consistently show that capital punishment is a substantial deterrent." Senator Orrin Hatch, 2002
Regression on nationally aggregated data can never yield reliable evidence on deterrence, pro or con. The signal, if any, is hopelessly buried in the noise. John Lamperti
Just as Messrs. Lott and Mustard can, with one model of the determinants of homicide, produce statistical residuals suggesting that 'shall issue' laws reduce homicide, we expect that a determined econometrician can produce a treatment of the same historical periods with different models and opposite effects. Econometric modeling is a double-edged sword in its capacity to facilitate statistical findings to warm the hearts of true believers of any stripe.
Franklin Zimring and Gordon Hawkins, “Concealed
Handguns: The Counterfeit Deterrent,” The Responsive
Community 7: 46-60, 1997
The Bell Curve by Herrnstein and Murray put American social scientists in an uncomfortable place. The conclusions of the book are unwelcome, while the methods of the book appear to be the standbys of everyday social science. The unstated problem for many commentators is how to reject the particular conclusions of The Bell Curve without also rejecting the larger enterprises of statistical social science, psychometrics, and social psychology.
Clark Glymour in Intelligence, Genes and Success: Scientists Respond to the Bell Curve
“there is much uncertainty as to the `correct’ empirical model that should be used to draw inferences, and each researcher typically tries dozens, perhaps hundreds, of specifications before selecting one or a few to report. Usually, and understandably the ones selected for publication are those that make the strongest case for the researcher’s prior hypothesis.”
The data analyzed are not sufficiently strong to lead researchers with different prior beliefs to reach a consensus regarding the deterrent effects of capital punishment. Right-winger, rational-maximizer, and eye-for-an-eye researchers will infer that punishment deters would-be murderers, but bleeding-heart and crime-of-passion researchers will infer that there is no significant deterrent effect.
Walter McManus, Journal of Political Economy, 1985
In many quantitative disciplines, most typically econometrics, the appropriate method is to assume a statistical model, then collect the data, then test the model by comparing the statistics with the model. If the model does not fit it is rejected. This is supposedly "sticking out one's neck," which is presumably the macho Popper things to do. There are various things problematic with this prescription… if you follow the prescription, and your data are any good, your head gets chopped off… people know their head will get chopped off, nobody follows the prescription. They collect data, look at their data, modify their model, look again, stick out their neck a tiny bit, modify the model again, and finally look around with a proud look on their face and a non-rejected model in their hand, pretending to have followed the Popperian prescription. Thus the prescription leads to fraud.
Jam de Leeuw in Trends and Perspectives in Empirical Social Research