21
jobs—the mid–level wage jobs. This means that low– and mid-level wage categories were
impacted with lower employment in the 1980s, while in the 1990s, the mid–level wage
workers were more heavily impacted. This reflects a trend toward greater loss for mid–
level wage workers.
Polarization of the job market means that there is employment growth for high-paying
and low-paying jobs, but less growth or even a decline in jobs with mid–level wages. The
explanation for this phenomenon is that routine jobs—whether they are manual or
cognitive—can be replaced by computers and offshoring.
We still need to be able to explain how it is possible that during the 1990s, the relative
wage of nonproduction labor increased, while employment fell. This contradicts the
predictions in our model. But, suppose that routine cognitive jobs done by nonproduction
workers were offshored or replaced by computers. These nonproduction routine workers
earned lower wages than the nonproduction nonroutine workers who were not replaced.
This means that the remaining workers in nonproduction earned an average higher wage