Citation increments between collaborating countries

International collaboration enhances citation impact. Collaborating with a country increments the citations received from it. But some collaborating countries provide greater increments in this sense than others, and likewise some countries receive greater increments from their partner countries than others. We observed a certain tendency for these increments to be lower in countries with greater impacts. Also, all the countries studied had higher Domestic Impacts as a result of collaborating, although this increment was less than that obtained from other countries. Finally, there were differences in the behaviour of the countries between the various scientific disciplines, with the effects being greatest in Social Sciences, followed by Engineering.