This study investigates knowledge structures and scientific communication using bibliometric methodsto explore scientific knowledge production and dissemination. The aim is to develop knowledgeabout this growing field by investigating studies using international large-scale assessment (ILSA) data,with a specific focus on those using Programme for International Student Assessment (PISA) data.As international organisations use ILSA to measure, assess and compare the success of nationaleducation systems, it is important to study this specific knowledge to understand how it is organisedand legitimised within research. The findings show an interchange of legitimisation, where majoractors from the USA and other English-speaking and westernised countries determine the academicdiscourse. Important epistemic cultures for PISA research are identified: the most important of whichare situated within psychology and education. These two research environments are epicentrescreated by patterns of the referrals to and referencing of articles framing the formulation of PISAknowledge. Finally, it is argued that this particular PISA research is self-referential and self-authorising,which raises questions about whether research accountability leads to ‘a game of thrones’, whererivalry going on within the scientific field concerning how and on what grounds ‘facts’ and ‘truths’ areconstructed, as a continuing process with no obvious winner.