(en) A great deal of evidence for the U.S. economy suggests that after changes in aggregate nominal demand prices move "sluggishly" toward their eventual long-term values, that output responds directly to these changes in demand, and these output effects linger "persistently" over time. Most econometric evidence suggests that something of the order of four to six years must pass before the ultimate effects on prices and output will be reached. As commonly interpreted, this lag has profoundly disturbing implications about the functioning of markets and about the rate of agents'expectations in macroeconomics.
Thurston, T. B. (1983). Price Flexibility and Output “Persistence” in the Postwar U.S. (Working Papers Institut des sciences économiques 8308). https://hdl.handle.net/2078.5/279038