Tag Archives: Statistics & Econometrics

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...

In plain terms, it is evident that if what is really the same factor is appearing in several places under various disguises, a free choice of regression coefficients can lead to strange results. It becomes like those puzzles for children where you write down your age, multiply, add this and that, subtract something else, and eventually end up with the number of the Beast in Revelation. Prof. Tinbergen explains that, generally speaking, he assumes that the correlations under...

There is a nice YouTube video with Tony O’Hagan interviewing Dennis Lindley. Of course, Dennis is a legend and his impact on the field of statistics is huge. [embedded content] At one point, Tony points out that some people liken Bayesian inference to a religion. Dennis claims this is false. Bayesian inference, he correctly points out, starts with some basic axioms and then the rest follows by deduction. This is logic, not religion. I agree that the mathematics of Bayesian...

On randomness and probability in economics Modern mainstream economics relies to a large degree on the notion of probability. To at all be amenable to applied economic analysis, economic observations have to be conceived as random events that are analyzable within a probabilistic framework. But is it really necessary to model the economic system as a system where randomness can only be analyzed and understood when based on an a priori notion of...

Living high and feeling low High-altitude areas — particularly the US intermountain states — have increased rates of suicide and depression, suggests a review of research evidence in the Harvard Review of Psychiatry. The increased suicide rates might be explained by blood oxygen levels due to low atmospheric pressure, according to the article by Brent Michael Kious, MD, PhD, of University of Utah, Salt Lake City, and colleagues … They analyzed 12 studies,...

“Doctor, it hurts when I p” A low-powered study is only going to be able to see a pretty big effect. But sometimes you know that the effect, if it exists, is small. In other words, a study that accurately measures the effect … is likely to be rejected as statistically insignificant, while any result that passes the p < .05 test is either a false positive or a true positive that massively overstates the … effect. … A conventional boundary, obeyed long...