How can we understand the uncertainties in high-stake measures such as PISA in relation to the claims that different authorities make from them? In this paper, we use a rather remarkable case from Sweden involving conflicting interpretations of the PISA 2018 results at a national political level and a fight over statistics between two national agencies: National Agency for Education and the National Audit Office. The aim of this paper is to unpack processes of interpretations and claims that are often black-boxed in PISA debates: How can we understand the process that led up to the fight and what followed? Our data consist of media articles, broadcasts from the national television and radio (2018-2021), reports and memos from the two-state authorities involved in this debate, and email conversations between the two. Our results stress the need for further transparency in how PISA data are collected and calculated.