Tag Archives: Statistics & Econometrics

Judea Pearl’s and Bryant Chen’s Regression and causation: a critical examination of six econometrics textbooks — published in Real-World Economics Review no. 65 — addresses two very important questions in the teaching of modern econometrics and its different textbooks — how is causality treated in general, and more specifically, to what extent they use a distinct causal notation. The authors have for years been part of an extended effort of advancing explicit causal modelling...

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The connection between cause and probability Causes can increase the probability​ of their effects; but they need not. And for the other way around: an increase in probability can be due to a causal connection; but lots of other things can be responsible as well … The connection between causes and probabilities is like the connection between a disease and one of its symptoms: The disease can cause the symptom, but it need not; and the same symptom can...

When odds ratios mislead (wonkish) A few years ago, some researchers from Georgetown University published in the New England Journal of Medicine a study that demonstrated systematic race and sex bias in the behavior of America’s doctors. Needless to say, this finding was widely reported in the media: Washington Post: “Physicians said they would refer blacks and women to heart specialists for cardiac catheterization tests only 60 percent as often as they...

Too much of ‘we controlled for’ The gender pay gap is a fact that, sad to say, to a non-negligible extent is the result of discrimination. And even though many women are not deliberately discriminated against, but rather self-select into lower-wage jobs, this in no way magically explains away the discrimination gap. As decades of socialization research has shown, women may be ‘structural’ victims of impersonal social mechanisms that in different ways...

Relative und absolute Risiken Das absolute Risiko einer medizinischen Intervention unterscheidet sich dabei vom relativen Risiko. Das wird an einem Beispiel klar: Angenommen, bei einem Test kann durch ein Medikament die Zahl der Erkrankungen von 10 auf 5 Fälle bei 1000 Personen reduziert werden. Relativ gesehen ist das eine Reduzierung des Krankheitsrisikos um 50 Prozent (5 von 10). Absolut gesehen sind es jedoch nur 0,5 Prozent (5 von 1000). Die erste Zahl...

Vad säger oss — egentligen — statistiska regressioner? En grupp ‘högpresterande’ elever — Ada, Beda, och Cissi — söker in till en friskola. Ada och Beda blir antagna och börjar på den. Cissi blir också antagen, men väljer att gå på en kommunal skola. En annan grupp ‘lågpresterande’ elever — bestående av Dora och Eva — söker och blir både antagna till en friskola, men Eva väljer att gå på en kommunal skola. Om vi nu tittar på hur de presterar på ett...

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Instrumentalvariabler och heterogenitet — en kommentar (wonkish) Användandet av instrumentalvariabler används numera flitigt bland ekonomer och andra samhällsforskare. Inte minst när man vill försöka gå bakom statistikens ‘korrelationer’ och också säga något om ‘kausalitet.’ Tyvärr brister det ofta rejält i tolkningen av de resultat man får med hjälp av den vanligaste metoden som används för detta syfte — statistisk regressionsanalys. Ett exempel från...

[embedded content] Economics may be an informative tool for research. But if its practitioners do not investigate and make an effort of providing a justification for the credibility of the assumptions on which they erect their building, it will not fulfil its task. There is a gap between its aspirations and its accomplishments, and without more supportive evidence to substantiate its claims, critics — like yours truly — will continue to consider its ultimate arguments as a...