The analysis presented has shown th

The analysis presented has shown that true real ICT investment-GDP share are higher than indicated by official statistics; and that there is a considerable share of internet value-added that, so far, is not covered at all by the System of National Accounts. Hence the role of ICT for economic growth is clearly underestimated by official statistics. The positive external effects of ICT re- search and development and ICT innovations, respectively, are most likely underestimated by policy makers and hence the promotion of ICT innovation is sub-optimal. It also is interesting to consider the role of the adaptation cost of ICT expansion. Since the internetis a truly global digital market, one should also considerthe role ofaninternationaldigital growthspillover. From the perspective ofthe EU countries an insufficient knowledge about cross-country spillovers leads us to expect that digital R&D promotion is inadequate.
It will be interesting to analyse the price dynamics of the ICT sector. As long as the relative ICT (investment) price index is falling relative to the price index for capital equipment the share of ICT investment in total investment is likely to increase and this in turn implies that the ICT capital stock relative to the total capital stock will rise. It would be interesting to analyse the implica- tions from such structural changes—this could include a rise of the output elasticity of capital which in turn has many important implications; e.g. the revenue- maximizingincometax rate in a growth model can be shown to be equal to 1-ß (Welfens 2013, p. 57) so that a rise of ß could bring about pressure for lower income tax rates world wide.
While the analysis here has presented findings for a rather limited range of countries a broader data base could allow a wider coverage in the future. The EU’s KLEMS database is quite useful but a broader global data set is needed. To the extent that the World Bank has increasingly emphasized the digital modernization of economies one may expect that member countries of the World Bank will collect broader data, including on the time budget of households on the internet. Survey results for both OECD, and other, countries on the split of the time budget into “digital consumption” and “digital value-added” would also be useful.