Drawing on a critical data studies as well as a tech design perspective, this chapter provides insights into the role and impact of (digital) data infrastructures as powerful new tools of relation making and decision support in everyday school monitoring and management. We hereby built on a large body of empirical material collected in past and ongoing research projects to show how, in both school monitoring and management, new powerful entanglements of actors and digital technologies (e.g. State Monitoring Data Systems, School Management Information Systems, Learning Management Software) around ‘[…] practices of sorting, naming, numbering, comparing, listing, and calculating’ (Lury et al., 2012: 3) have been promoting an increasingly ‘datafied’ school, yet not in linear, but rather in ‘messy’ ways. We use the example of (re)fabricating inequality to illuminate this messiness, which appears when inequality becomes inscribed into school monitoring/management tools as well as when inequality becomes (re)fabricated as soon as people work with these tools. Our findings suggest that while the datafication of school monitoring and management tools does increase the transparency in schools´/state agencies´ decision-making and teaching practices, it may also result in impactful inequalities of dataveillance. This ambivalence is constitutive for deep mediatization as an ongoing transformation process of the society at large.