[harshpotatoes]

ErSo, there are a few things I don't quite understand. In the original study, Renhart had erroneously averaged 7 numbers together to get a slightly negative growth. The 'correct' result is obtained from averaging eight numbers together, resulting in slightly positive growth. What is unclear to me, is how are either of these numbers considered to be very significant? With so few samples in the average, I would draw the conclusion that both measurements agree with one another and the error bars for their measured result are quite a bit larger than they seem to be suggesting. Is this common in economics?

[jessriedel]

Macroecon has the simultaneous hindrances of (1) not being able to run a controlled experiment and (2) a dearth of data. It doesn't excuse people for being far too confident in the conclusions they draw, but it does explain why such large differences of opinions can persist (especially on such a politically charged subject). People can't be pulled away from their priors.

[dragonwriter]

> Macroecon has the simultaneous hindrances of (1) not being able to run a controlled experiment and (2) a dearth of data.

Well, except #1 should be "not being able to run experiments in laboratory conditions". Statistical controls in an experiment are still controls, and it is still possible though (because of the point made briefly by #2, to run statistically-controlled experiments) sometimes of limited utility; the dearth of data (specifically, the small number of data points compared to the number of independent variables that need to be controlled for) is what limits the utility of many experiments with statistical controls in the field.

[jacques_chester]

Even if you use rigorous statistical techniques -- and economists do under the heading of econometrics, even inventing new techniques -- it's still really hard to draw meaningful conclusions.

There are just so many variables. And the more interconnected the world becomes, the more variables there are. Pointing to any one correlation and you'll find a hundred statistical fingers pointing at correlations with totally different consequences.

[dragonwriter]

> Even if you use rigorous statistical techniques -- and economists do under the heading of econometrics, even inventing new techniques -- it's still really hard to draw meaningful conclusions.

> There are just so many variables.

Right. That's the problem with too few data points given the number of independent variables that need to be controlled for. I addressed that explicitly.

[pseut]

Political constraints and welfare concerns effectively rule out "controlled experiment" at the present time.

[jessriedel]

Agreed.