In general—in general—analysis of relative efficiency of tax from a revenue perspective, from a non-distorting of economic activity perspective.... In general, value-added taxes are the most efficient mechanism. There are issues.... As with all tax policy, though, one has to worry about distributional consequences, regressivity, if you will—that's a word—and other political economy factors. But if you're just looking at efficiency of raising revenue and not distorting economic activity in general, the value-added tax, set at a relatively low level, would be the most efficient mechanism.
On February 12th, 2013. See this statement in context.