This paper examines the impact of the Organisation for Economic Cooperation and Development's Programme for International Student Assessment (PISA) in two national policy contexts: Canada and Australia. Drawing on theories of globalisation and affect, the paper explores 'catalyst data' and its effects in these contexts to show how affective responses to mediations of PISA performance have become important levers for policy change. Two empirical cases of the role of data in the globalisation of schooling are discussed. The first case examines responses in Canada to the PISA 2012 results, which generated senses of anxiety among parents that coalesced into a view that Albertan schools faced a mathematics crisis. The second case interrogates how, since PISA 2009, a narrative about the declining quality of Australian schooling has become dominant in political discourse and in media representations. The paper compares and contrasts the affective effects of data across both contexts.