For example, economists have found that industries and firms that spend more on research and development or invest more in information technologies hire relatively more high-skilled workers and spend a relatively larger share of their payrolls on them (Autor, Katz, and Krueger, 1998; Bartel and Sicherman, 1999; Berndt and Morrison, 1995; Berman, Bound, and Griliches, 1994).
Although skill-biased technical change appears to be an important cause of the rise in earnings inequality, it does not provide a complete explanation for that trend. The hypothesis cannot explain, for example, why the sharp rise in investment in information technology in the 1990s was not accompanied by a higher rate of increase in wage inequality.