- Private property rights (to generate incentives)
- Reliable legal framework (to correct externalities and constrain predation)
- Stable monetary system (to maximise information)
- Free Trade (and the embrace of markets)
Note that whether you subscribe to the above is not the issue, it's whether the above is an accurate depiction of the consensus of professional economists. One student challenged this, in particular the final point regarding free trade. Whether I'm accurate or not, here is the reasoning behind my claim.
- Fuller, D. and D. Geide-Stevenson (2003). Consensus among economists: Revisited. Journal of Economic Education 34 (Fall): 369-87. According to the abstract, "the authors generally find consensus within the profession... consensus is particularly strong for propositions of free international trade and capital flows"
- Whaples, Robert (2006). "Do Economists Agree on Anything? Yes!". The Economists' Voice 3 (9). This paper uses survey data to find that 87.5 percent of the members of the American Economic Association agree that "the U.S. should eliminate remaining tariffs and other barriers to trade."
- Caplan, Bryan. 2002. "Systematically Biased Beliefs About Economics: Robust Evidence of Judgmental Anomalies from the Survey of Americans and Economists on the Economy." Economic Journal, 112(479): 433-458. Asked whether "trade agreements between the US and other countries" is a "2 = major reason", "1 = minor reason", or "0 = not a reason at all" for why the economy is not doing better than it is, the average score for economists is 1.87 [note: Caplan uses the Survey of Americans and Economists on the Economy data set]
Also, I think it's worth listening to the informal judgment of other prominent economists on this. Given that I did my PhD at George Mason I would expect to overestimate the avocation of free markets within the economics profession. Indeed that's why I enjoyed Bryan Caplan's classes so much, because he actually tests for this. But I think useful testing points are Greg Mankiw and Paul Krugman. Firstly, here's what Mankiw has said on this topic:
Few propositions command as much consensus among professional economists as that open world trade increases economic growth and raises living standards. Smith’s insights are now standard fare in Econ 101.
Finally, Paul Krugman - have a look at Pop Internationalism, or his essay on "Ricardo's Difficult Idea" (note: I don't think the principle of comparative advantage is difficult). Despite his more recent NYT columns, if you look at the body of Krugman's academic work you find someone who uses the basic principle of trade theory, and accepts it. When Mankiw and Krugman agree , I'd say that's pretty close to a definition of consensus.
If there's other survey data out there I'm not aware of, I'd love to see it. Obviously the above is susceptible to the charge that it's heavily skewed towards Americans. But the AEA is not a national organisation - I am a member. Indeed if you're not a member of the AEA it's more likely to be a reflection of an individual's credibility as an economist than a sign of a biased data set.