-More pressing is the question whether international assistance for production of GPGs in Country X reduced international assistance for production of non-GPGs in Country X. A direct answer to this question is difficult to provide because data on foreign assistance at the level of destination countries are much worse than data by country of origin. Reisen et al [21] , looking at the latter, concluded that the average bilateral donor's allocation of US$1 to GPG production reduced its spending on non-GPG foreign assistance by US$0.25.