I apologize for nit-picking, but I think advocates of liberalization hurt their cause when they overstate their case. Johan Norberg writes:

I still meet anti-capitalists who claim that liberalisation and market reform destroy economies and increase poverty. Why don´t they take a look at this graph from the new Index of Economic Freedom 2006. Per capita growth in the countries that liberalised the most since 1995 has been almost three times higher than in those where economic freedom declined.

Let’s stop pretending that trade liberalization skeptics are ridiculous for not hailing the truth of this and similar bar graphs. Anyone that took AP Statistics in high school can produce a sufficient number of objections to render this evidence inconclusive: correlation isn’t causation, the causal relation may be bidirectional or run the other way, lurking variables may be omitted, etc.

In Norberg’s defense, in spite of titling his post “freer and richer,” he actual formulates a weaker claim — liberalization does not destroy economies and increase poverty. It appears true that improvements in a country’s economic freedom score do not negatively affect growth so much as to overwhelm other engines of growth. But “liberalization isn’t harmful” is a far cry from “liberalization is helpful.” Moreover, the bar graph describes per capita GDP growth, not poverty reduction. There is plenty of evidence that economic growth reduces poverty, but I think it’s a bit sloppy to conflate the two.