摘要：There has been a remarkable increase in wage inequality in the US, UK and many
other countries over the past three decades. A significant part of this appears
to be within observable groups (such as age-gender-skill cells). A generally
untested implication of many theories rationalizing the growth of within-group
inequality is that firm-level productivity dispersion should also have
increased. Since the relevant data do not exist in the US we utilize a UK
longitudinal panel dataset covering the manufacturing and non-manufacturing
sectors since the early 1980s. We find evidence that productivity inequality has
increased. Existing studies have underestimated this increased dispersion
because they use data from the manufacturing sector which has been in rapid
decline. Most of the increase in individual wage inequality has occurred because
of an increase in inequality between firms (and within industries). Increased
productivity dispersion appears to be linked with new technologies as suggested
by models such as Caselli (1999) and is not primarily due to an increase in
transitory shocks, greater sorting or entry/exit dynamics
