DEFINITION: Investment in knowledge is defined and calculated as the sum of expenditure on R&D, on total higher education (public and private) and on software. Simple summation of the three components would lead to overestimation of the investment in knowledge owing to overlaps (R&D and software, R&D and education, software and education). Therefore, data reported here have been adjusted to exclude the overlaps between components. Note that as the term is used here, "investment” has a broader connotation than its usual meaning in economic statistics. It includes current expenditures, such as on education and R&D, as well as capital outlays, such as purchases of software and construction of school buildings.