Cheers William. Not sure about this line though: "It is important to note, however, that a change from an inefficient allocation to an efficient one is not necessarily a Pareto improvement." Doesn't that depend on how you're defining efficiency?

The wikipedia link's first reference is very interesting - I'd not seen it: the relevance of efficiency to different theories of society in 'Economics of the Welfare State' by Nicolas Barr. It's actually got a breakdown of meanings of efficiency for libertarian/socialist/utilitarian/Rawlsian. Which is actually a rather more effective way of showing that hegemonic economic ideas have political content...