Lars P. Syll

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Econometrics — a matter of BELIEF and FAITH Everybody who takes regression analysis course, studies the assumptions of regression model. But nobody knows why, because after reading about the axioms, they are rarely mentioned. But the assumptions are important, because if any one assumption is wrong, the regression is not valid, and the interpretations can be completely wrong. In order to have a valid regression model, you must have right regressors, the...

Econometrics and the Axiom of Omniscience Most work in econometrics and regression analysis is — still — made on the assumption that the researcher has a theoretical model that is ‘true.’ Based on this belief of having a correct specification for an econometric model or running a regression, one proceeds as if the only problem remaining to solve have to do with measurement and observation. When things sound to good to be true, they usually aren’t. And that...

Econometrics — fictions masquerading as science In econometrics one often gets the feeling that many of its practitioners think of it as a kind of automatic inferential machine: input data and out comes casual knowledge. This is like pulling a rabbit from a hat. Great — but first you have to put the rabbit in the hat. And this is where assumptions come into the picture. As social scientists — and economists — we have to confront the all-important question...

Stjärnorna kvittar det lika [embedded content] Till minnet av Bengt — en vän non plus ultra

On the road to hell  [embedded content]

The logic of instrumental variables (student stuff)  [embedded content]

Macroeconometrics — the science of hubris When a macroeconometrician uses regression, he or she is implicitly saying, in effect, that the third quarter of 2007 is the same as the first quarter of 1988, once all factors that might be different between those two quarters are controlled for. The idea is that the economist is conducting an intertemporal quasi-experiment. But because there is only one economic history with which to work, there is a lack of...

 [embedded content] Jättebra video. Låt oss hoppas att LO nu rejält påminner “sitt” eget parti om det gigantiska svek de utsatt sina väljare för. Historiens dom ska falla hård på ansvariga politiker — och inte minst på socialdemokratins Göran Persson, Kjell-Olof Feldt och alla andra som i deras fotspår fortsatt glatt traska patrull — som hänsynslöst och med berått mod låtit offra den en gång så stolta svenska traditionen av att försöka bygga ett jämlikt samhälle. Ett samhälle...

Selection bias and the elite school illusion  [embedded content] A great set of lectures — but I still warn my students that regression-based averages is something we have reasons to be cautious about. Suppose we want to estimate the average causal effect of a dummy variable (T) on an observed outcome variable (O). In a usual regression context one would apply an ordinary least squares estimator (OLS) in trying to get an unbiased and consistent estimate: O...