I called for more empirical work on the effects of liberty:

Libertarians focus too much on trying to argue abstractly that liberty would be better, and not enough on just concretely describing how liberty would be different. … From [our] vast literature we should be able to identify many concrete patterns and “stylized facts” about how government-provision and heavy-regulation tends to change products and services. (more)

David Henderson agrees:

The reality is that after Stigler’s speech, many economists did look more at the data and the data tended to show that the free market and economic freedom work better than government control. But Robin is not satisfied. There is more to be done, he says, and he’s right.  (more)

But he does have a criticism:

I do have one main criticism of Robin’s post. … It’s the West/East Germany and the South/North Korea comparisons that I want to defend. With all the variables that could affect economic growth, think about how hard it is to know what some of the most important factors are. … The stark contrast between those two pairs of countries and what that said about some economic freedom versus harsh totalitarianism.

I very much agree that those nation pairs make useful comparisons; sorry that what I wrote could mislead on that point. These comparisons do indeed suggest that “some freedom” is better than “harsh totalitarianism”, and they are good data-points on which to base stylized facts on the general effects of more liberty. Their main limitations are that they don’t say much directly about the effects of a lot more liberty than is found in West Germany or South Korea. To imagine even more liberty, we need those stylized facts.