  We analyze international co-authorship relations in the Social Science
Citation Index 2011 using all citable items in the DVD-version of this index.
Network statistics indicate four groups of nations: (i) an Asian-Pacific one to
which all Anglo-Saxon nations (including the UK and Ireland) are attributed;
(ii) a continental European one including also the Latin-American countries;
(iii) the Scandinavian nations; and (iv) a community of African nations. Within
the EU-28 (including Croatia), eleven of the EU-15 states have dominant
positions. Collapsing the EU-28 into a single node leads to a bi-polar
structure between the US and EU-28; China is part of the US-pole. We develop an
information-theoretical test to distinguish whether international
collaborations or domestic collaborations prevail; the results are mixed, but
the international dimension is more important than the national one in the
aggregated sets (this was found in both SSCI and SCI). In France, however, the
national distribution is more important than the international one, while the
reverse is true for most European nations in the core group (UK, Germany, the
Netherlands, etc.). Decomposition of the USA in terms of states shows a
similarly mixed result; more US states are domestically oriented in SSCI,
whereas more internationally in SCI. The international networks have grown
during the last decades in addition to the national ones, but not by replacing
them.
