The introductory article of the GSE special issue 'PISA for scandalization, PISA for projection: the use of international large-scale assessments in education policy making' contextualises the four articles of the special issue in the broader context of comparative policy studies in education. It reflects in particular on the question of why cross-national comparison is relevant for the study of ILSA (international large-scale assessment) policy reception and how 'methodological nationalism' may be avoided when using national education systems as units of analysis.