Lars P. Syll

Is economics nothing but a library of models? Chameleons arise and are often nurtured by the following dynamic. First a bookshelf model is constructed that involves terms and elements that seem to have some relation to the real world and assumptions that are not so unrealistic that they would be dismissed out of hand. The intention of the author, let’s call him or her “Q,” in developing the model may be to say something about the real world or the goal may...

Chebyshev’s and Markov’s Inequality Theorems Chebyshev’s Inequality Theorem — named after Russian mathematician Pafnuty Chebyshev (1821-1894) — states that for a population (or sample) at most 1/k2 of the distribution’s values can be more than k standard deviations away from the mean. The beauty of the theorem is that although we may not know the exact distribution of the data — e.g. if it’s normally distributed  — we may still say with certitude (since the...

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The empirical turn in economics Ce qui fait l’unité de la discipline est plutôt l’identification causale, c’est-à-dire un ensemble de méthodes statistiques qui permettent d’estimer les liens de cause à effet entre un facteur quelconque et des résultats économiques. Dans cette perspective, la démarche scientifique vise à reproduire in vivo l’expérience de laboratoire, où l’on peut distinguer aisément la différence de résultat entre un groupe auquel on...

How many permutations exist of the ten digits (0-9) that either begin with”123″, contain “56” in the 6th & 7th positions, or end with “789”?

If you have an apple and I have an apple and we exchange these apples then you and I will each have one apple. But if you have an idea and I have an idea and we exchange these ideas, then each of us will have two ideas. George Bernard Shaw Adam Smith once wrote that a really good explanation is “practically seamless.” Is there any such theory within one of the most important fields of social sciences — economic growth? In Paul Romer’s Endogenous Technological Change (1990)...

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On models and simplicity When it comes to modelling yours truly does see the point emphatically made time after time by e. g. Paul Krugman about simplicity — at least as long as it doesn’t impinge on our truth-seeking. ‘Simple’ macroeconomic models may of course be an informative heuristic tool for research. But if practitioners of modern macroeconomics do not investigate and make an effort of providing a justification for the credibility of the simplicity...

How to prove things .[embedded content] Great lecture series. Yours truly got Solow’s book when he was studying mathematics back in the 80s. Now in its 6th edition, it’s better than ever.

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