“In the 1970s and 1980s employment in quintessentially middle-skilled, middle-income occupations—salespeople, bank clerks, secretaries, machine operators and factory supervisors—grew faster than that in lower-skilled jobs. But around the early 1990s, something changed. Labour markets across the rich countries shifted from a world where people’s job and wage prospects were directly related to their skill levels. Instead, with only a few exceptions, employment in middle-class jobs began to decline as a share of the total while the share of both low- and high-skilled jobs rose (see chart). The pattern was similar in countries with very different levels of unionisation, prevalence of collective bargaining and welfare systems. This “polarisation” of employment almost certainly had a common cause. The development of information technology (IT) is the leading candidate. Computers do not directly compete with the abstract, analytical tasks that many high-skilled workers do, but aid their productivity by speeding up the more routine bits of their jobs. But they do directly affect the need for people like assembly-line workers or those doing certain clerical tasks, whose jobs can be reduced to a set of instructions which a machine can easily follow (and which can consequently be mechanised). At the other end of the employment spectrum, as the example of the towel-folding robot neatly demonstrates, low-skilled jobs may not require much education but they are very hard to mechanise.”