The effectiveness of inter-organizational collaboration rely on several factors, among which the composition of cooperation participants (partners in the inter-organizational network) and the number of cooperation participants (size of the network) play an important role. Thus, it is crucial to have a reliable estimate of the number of alters and the composition of collaboration networks. This task can be viewed as a particular case of hard-to-reach population estimation. In this work, we propose an adaptation of capture-recapture approach to estimate the number of actors in the personal networks of firms participating in the POR-FESR 2007-2013 call in Friuli Venezia Giulia (a region in the north-east of Italy). The alters (other organizations, also not regionally bounded) they listed in their network before and after their participation to the call will be considered as the two lists on which the proposed capture-recapture approach is applied.
