Lars P. Syll

Some common misunderstandings about randomization Randomization is an alternative when we do not know enough to control, but is generally inferior to good control when we do. We suspect that at least some of the popular and professional enthusiasm for RCTs, as well as the belief that they are precise by construction, comes from misunderstandings about … random or realized confounding on the one hand and confounding in expectation on the other … The RCT...

Modern economics — a severe case of model Platonism That is the great thing about abstraction. Working with what can be called ‘flex price’ models does not imply that you think price rigidity is unimportant, but instead that it can often be ignored if you want to focus on other processes. Simon Wren-Lewis When applying deductivist thinking to economics, mainstream economists like Wren-Lewis usually set up ‘as if’ models based on a set of tight axiomatic...

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Deductivist modeling endeavours and an overly simplistic use of statistical and econometric tools are sure signs of the explanatory hubris that still haunts mainstream economics. In an interview Robert Lucas says the evidence on postwar recessions … overwhelmingly supports the dominant importance of real shocks. So, according to Lucas, changes in tastes and technologies should be able to explain the main fluctuations in e.g. the unemployment that we have seen during the last...

Tractability, truth, and ignorability Most attempts at causal inference in observational studies are based on assumptions that treatment assignment is ignorable. Such assumptions are usually made casually, largely because they justify the use of available statistical methods and not because they are truly believed. Marshall Joffe et al. An interesting (but from a technical point of view rather demanding) article on a highly questionable assumption used in...

Berkson’s paradox or why attractive people you date tend​ to be jerks Have you ever noticed that, among the people you date, the attractive ones tend to be jerks? Instead of constructing elaborate psychosocial theories, consider a simpler explanation. Your choice of people to date depends on two factors, attractiveness and personality. You’ll take a chance on dating a mean attractive person or a nice unattractive person, and certainly a nice attractive...

Wage discrimination and the dangers of ‘controlling for’ confounders You see it all the time in studies. “We controlled for…” And then the list starts. The longer the better. Income. Age. Race. Religion. Height. Hair color. Sexual preference. Crossfit attendance. Love of parents. Coke or Pepsi. The more things you can control for, the stronger your study is — or, at least, the stronger your study seems. Controls give the feeling of specificity, of...

The cost of focusing on general equilibrium theory The largest problem with the economics profession’s focus on general equilibrium theory is the opportunity costs of that exploration. Important policy problems are not addressed. Consider Pareto optimality and the welfare theorems, which Fisher sees as the underpinnings of Western capitalism. In a world, such as ours, where property rights cannot be allocated effortlessly and costlessly, economist’s welfare...