This document outlines a study evaluating the socio-economic impacts of biobank networking projects. Preliminary results from interviews with members of six biobank networks show several effects, including networking and knowledge transfer. Key factors for generating effects include the size and maturity of biobanks and networks. The study aims to inform evaluation of BBMRI by distinguishing effects of biobanks versus networking and quantifying direct versus indirect impacts, though challenges remain around sampling, attribution and complexity.