where, here and throughout, notations like Uct, Ult, Flt, and Fkt denote the derivatives
of the utility function and the production function with respect to their arguments.
CKM show that the efficiency and labor wedges together account for essentially
all the movement in US output, and that the labor wedge plays a central role in
accounting for the movement in US labor for the Great Depression period and in
postwar business cycles.