How do firms respond to technological advances that facilitate the automation of tasks? Which tasks will they automate, and what types of worker will be replaced as a result? We present a model that distinguishes between a task's engineering complexity and its training requirements. When two...

Job polarization the rise in employment shares of high and low skill jobs at the expense of middle skill jobs occurred in the US not just recently, but also in the late nineteenth and early twentieth centuries. We argue that in each case polarization resulted from increased automation, and...