This article addresses the question of how and in what terms states constitute ethnicity and citizenship around statistical categories when these categories lack explicitly ethnic principles of classification. It does so based on a qualitative content analysis of the way that the German statistical category of 'persons with a migration background' is deployed in parliamentary debates on education. We argue that state actors in organized politics, who are embedded in Germany's national cultural repertoire and integration policy repertoire, transform this nuanced statistical category into a homogenized social category that is defined in terms of language, class and exclusion from the imagined national community. Our findings demonstrate that, in order to understand how the state uses statistics to draw boundaries within a society, it is necessary to go beyond the content of statistical categories themselves.