This study employs the concept of IT infrastructure to consider the inside of black box used in input-oriented IT productivity studies. This study differentiates IT infrastructure from other ITs that perform business functions directly. IT infrastructure has great contribution on IT productivity by supporting the appropriate use of other ITs (applications). Thus it is argued that in measuring IT productivity, the contribution of IT infrastructure investment should be considered separately within the measured IT investment (i.e. total IT spending).
Choi, Haiwook, "Information Technology Infrastructure as a Moderator of Organization's IT Productivity: An Economic Perspective" (1998). AMCIS 1998 Proceedings. 241.