Brynjolfsson, E. and A. McAfee (2011), Race Against The Machine: How the Digital Revolution is Accelerating Innovation, Driving Productivity, and Irreversibly Transforming Employment and the Economy. Digital Frontier Press. 2 See, e.g., evidence presented in Constâncio, V. (2016), “The challenge of low real interest rates for monetary  policy”, Lecture at the Macroeconomics Symposium, Utrecht School of Economics, 15 June.
3 For a more detailed analysis of issues relating to index calculation, see Diewert, W. E. (1998), “Index Number  Issues in the Consumer Price Index”, Journal of Economic Perspectives, 12(1): 47–58 and von der Lippe, P. (2007), Index Theory and Price Statistics, Peter Lang, Frankfurt am Main. 4 The direction of the bias for the aggregate index is less certain.