In this chapter, we approach educational leadership and subjectivity through the framework of necropolitics (Mhembe) and by exploring racialisation in practices of data-informed leadership in schools. Today, student subjectivities are split into measurable units (attainment, well-being, motivation e.g.). These pieces of measured life are elements in decision making related to possible interventions. While data seems to go easy with a representational framework, we argue for a performative approach in analysing how data matter, and we focus especially on the subjectifying effects of data. Concepts from black studies allow us to articulate the production and intersection of dark data and ethnic-racialised subjectivities. Biopolitical analyses of the potentialization of life have played a pivotal role in education, whereas necropolitical analyses of deciding ‘who may live and who may die’ as part of potentialisation are rare. In the case of the datafication of educational subjectivities, it is expedient to broaden the conceptual approach of biopolitics by emphasizing the issue of affect, death and waste, and exploring how, where, when and why data-informed leadership is ‘letting subjectivities die’ and depotentializing certain ‘genres of being human’ (Wynter; Weheliye).