BIG encompasses 47 members worldwide, which are collaborative research groups or trials data centres represented by one voting and several non-voting delegates within the BIG network. The final decision-making body of BIG is its General Assembly, consisting of the members embodied by their voting representatives.
Some BIG groups are regional, some are national and several are international. Each is associated with several to several hundred member hospitals and investigators. This represents approximately 3000 institutions worldwide.
Three new members joined the BIG network in 2010, bringing along their own local experience and further enriching BIG's capabilities as an international network: