In several past posts, I've been taken to task for using the CBO measure of the output gap (and the associated measure of potential GDP) [0] [1]. Some criticize the false sense of certainty that is provided by the official measures, since they are known to be revised as data comes in. Some criticize the measures on the basis the fact that the statistical methodologies (Hodrick-Prescott, Band-Pass) are divorced from a formal economic model. Some criticize the concept of potential GDP derived from a production function approach (i.e., thinking about the economy as one big production function associated with one big firm...). Arnold Kling's recent critique centers upon the idea that output is not homogenous, and we need different types of capital (and by extension labor) when the desired composition of output changes. Yet another -- not entirely unrelated -- perspective argues that when relative prices change