Pat Gunning wrote: "The whole idea of a shock seems a bit weird, doesn't it? Why call a change in market supply a "shift" and a change in aggregate supply a "shock?" This language seems more journalistic than scientific." The thinking, I suspect, goes back to Frisch's "Propagation and Impulse Problems in Dynamic Economics" (in /Economic Essays in Honor of Gustav Cassel/, 1933). As far as I can tell, the language did not become widespread until the mid-1970s. The oldest JSTOR entry for "demand shock" is Lucas's (1975) "An Equilibrium Model of the Business Cycle" (JPE) ; and the oldest entry for "supply shock" is Gordon's "Alternative Responses to External Supply Shocks" (Brookings Papers, 1975). Both write as if the terminology is already established. Pat Gunning wrote: "By the way, didn't you say that you are writing a macro text? How do you treat the AD/AS stuff in your text?" Anyone is welcome to look at my textbook in progress: http://econ.duke.edu/~kdh9 Kevin Hoover