Jason Smith — All models are wrong, but some are tedious

All models are wrong is properly taken as a rallying cry against tedium. Macroeconomists should not be adding variables and complications to their models because there simply isn't enough data to warrant doing so. Read Nate Silver on overfitting -- there are only about 200 quarterly observations of economic data in the post-war US economy where data is relatively good, which implies that a model should at most have about 10 parameters (some DSGE models have 40 parameters or more!). Noah Smith likes to say that macro data is uninformative. Really what that means is that economists have ignored Box: they shouldn't have so much overparameterization. With fewer parameters, the data isn't uninformative ... if you just have two parameters, the data is actually completely informative.

Information Transfer Economics
All models are wrong, but some are tedious

Jason Smith