‘Ideally controlled experiments’ tell us with certainty what causes what effects — but only given the right closures. Making appropriate extrapolations from (ideal, accidental, natural or quasi) experiments to different settings, populations or target systems, is not easy. ‘It works there’ is no evidence for ‘it will work here.’ Causes deduced in an experimental setting […]
Statistics & Econometrics
Modularity is the mark of a type of independence from context. The same functional relationship between variables will hold in a given component of the contributing mechanisms whether or not there is a change in a different component. The total effect may change when different components contribute, but the operation of the modular mechanism will […]
. Yours truly has for several years been conducting a doctoral course in statistics for students in educational science where SPSS has been used. Unfortunately, Bayesian analysis has not been available in that program. With version 29 of SPSS, things have changed. So, next year, there will be a new addition to the course!
Many journal editors request authors to avoid causal language, and many observational researchers, trained in a scientific environment that frowns upon causality claims, spontaneously refrain from mentioning the C-word (“causal”) in their work … The proscription against the C-word is harmful to science because causal inference is a core task of science, regardless of whether […]
. As always a pleasure listening to Edward Leamer and his critical views on the (mis)uses of statistical methods in empirical research. Main message: without a deep understanding of context, statistical and econometric analyses are useless!
. Many economists — yours truly included — are highly sceptical of the ability of mainstream economics to deliver useful models. Some of us even question the ‘modern’ insistence on modelling — “if it’s not in a model, it’s not economics.” Even if we accept the limitation of only being able to say something about […]
Always, but always, plot your data. Remember that data quality is at least as important as data quantity. Always ask yourself, “Do these results make economic/common sense”? Check whether your “statistically significant” results are also “numerically/economically significant”. Be sure that you know exactly what assumptions are used/needed to obtain the results relating to the properties of any estimator or […]
Pearl asserts, while some RCM (Rubin Causal Models) theorists deny, that so-called “non-manipulable” variables can be causes (Pearl 2019; Holland 1986, 2008). Race and gender, which arguably cannot be experimentally manipulated, are key examples of such variables … My response is that although advocates of the frameworks adopt conflicting positions regarding certain variables, these positions […]
Researchers adhering to missing data analysis invariably invoke an ad-hoc assumption called “conditional ignorability,” often decorated as “ignorable treatment assignment mechanism”, which is far from being “well understood” by those who make it, let alone those who need to judge its plausibility. For readers versed in graphical modeling, “conditional ignorability” is none other than the […]