This chapter will set the background of the modelling of PSI reuse economy. After introducing the unique characteristics of the economy associated to PSI reuse, it will focus on the review of existing specific approaches, which provides partial analysis for our research question in the context of the organizational knowledge creation theory (Nonaka, 1994). Secondly, the proposed theoretical model is described and one of its parts, the one that will be tested with real data, is analysed in further detail. Then, for this part of the model, the value chain of PSI reuse is described in order to understand which agents are involved and what role they play. It ends with a description of the theoretical framework for assessing data information sources according to a new standardization of reusability.