There is a widespread belief among economists that adding additional variables to a regression model causes higher standard errors. This note shows that, in general, this belief is unfounded and that the impact of adding variables on coefficients' standard errors is unclear. The concept of...

The fundamental problem of external validity is not to generalize from one experiment, so much as to experimentally test generalizable theories. That is, theories that explain the systematic variation of causal effects across contexts. Here we show how the graphical language of causal diagrams...

Economists disagree; this is a matter of fact. Economics has an empirical methodology to verify whatever theories economists from different schools of thought advance in order to explain the economic phenomenon. This empirical methodology lends economists the confidence that most of the...

Economists sometimes interpret the failure of a significance test to disconfirm a hypothesis as evidence that this hypothesis is valid. Six examples of this are cited from recent journals. But this is a misinterpretation of what significance tests show. While in general it is correct that every...

Investors sometimes have strong convictions that a distinctive economic regime will prevail in the period ahead and therefore would like to form a portfolio that reflects the expected returns, standard deviations, and correlations of assets during such a regime. To do so, they typically isolate...

We build on Rosenzweig and Wolpin (2000) and Keane (2010) and show that in order to fulfill the Instrumental variable (IV) identifying moment condition, a policy must be designed so that compliers and non-compliers either have the same average error term, or have an error term ratio equal to...

The primary aim of the paper is to place current methodological discussions on empirical modeling contrasting the 'theory first' versus the 'data first' perspectives in the context of a broader methodological framework with a view to constructively appraise them. In particular, the paper focuses...

The primary aim of the paper is to place current methodological discussions in macroeconometric modeling contrasting the 'theory first' versus the 'data first' perspectives in the context of a broader methodological framework with a view to constructively appraise them. In particular, the paper...