Tag Archives: Statistics & Econometrics

In his new history of experimental social science — Randomistas: How radical researchers are changing our world — Andrew Leigh gives an introduction to the RCT (randomized controlled trial) method for conducting experiments in medicine, psychology, development economics, and policy evaluation. Although it mentions there are critiques that can be waged against it, the author does not let that shadow his overwhelmingly enthusiastic view on RCT. Among mainstream economists, this...

Econometrics cannot establish the truth value of a fact. Never has. Never will. There seems to be a pervasive human aversion to uncertainty, and one way to reduce feelings of uncertainty is to invest faith in deduction as a sufficient guide to truth. Unfortunately, such faith is as logically unjustified as any religious creed, since a deduction produces certainty about the real world only when its...

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Probability and rationality — trickier than you might think The Coin-tossing Problem My friend Bengt says that on the first day he got the following sequence of Heads and Tails when tossing a coin: H H H H H H H H H H And on the second day he says that he got the following sequence: H T T H H T T H T H Which day-report makes you suspicious? Most people I ask this question says the first day-report looks suspicious. But actually,​ both days are equally...

The main reason why almost all econometric models are wrong Since econometrics doesn’t content itself with only making optimal predictions, but also aspires to explain things in terms of causes and effects, econometricians need loads of assumptions — most important of these are additivity and linearity. Important, simply because if they are not true, your model is invalid and descriptively incorrect.  And when the model is wrong — well, then it’s wrong. The...

Last year, we recruited 29 teams of researchers and asked them to answer the same research question with the same data set. Teams approached the data with a wide array of analytical techniques, and obtained highly varied results … All teams were given the same large data set collected by a sports-statistics firm across four major football leagues. It included referee calls, counts of how often referees encountered each player, and player demographics including team position,...

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“Mediation analysis” is this thing where you have a treatment and an outcome and you’re trying to model how the treatment works: how much does it directly affect the outcome, and how much is the effect “mediated” through intermediate variables … In the real world, it’s my impression that almost all the mediation analyses that people actually fit in the social and medical sciences are misguided: lots of examples where the assumptions aren’t clear and where, in any case,...

Haavelmo and Frisch on the limited value of econometrics For the sake of balancing the overly rosy picture of econometric achievements given in the usual econometrics textbooks today, it may be interesting to see how Trygve Haavelmo — with the completion (in 1958) of the twenty-fifth volume of Econometrica — assessed the role of econometrics in the advancement of economics. Although mainly positive of the “repair work” and “clearing-up work” done, Haavelmo...

Statistics and econometrics are not very helpful for understanding economies A statistician may have done the programming, but when you press a button on a computer keyboard and ask the computer to find some good patterns, better get clear a sad fact: computers do not think. They do exactly what the programmer told them to do and nothing more. They look for the patterns that we tell them to look for, those and nothing more. When we turn to the computer for...