The use of data for governance purposes has been widely recognised as a way for national authorities to coordinate their activities across administrative levels and improve educational quality. This places the mid-central authority--in many countries the municipal level--in the midst of modern education governing. This article reports a case study analysis of the particular uses of performance data and numbers by mid-central municipal authorities in the daily work of governing schools in Norway. The three empirical case studies combine an analysis of policy document and fieldwork interviews with municipal administrators. The article contributes important insights into the role of municipal administrators as interpreters of policy goals at a crucial yet understudied level of the education system. In contrast to the dominant perspective in the data use literature, which often addresses implementation and the effectiveness of how numbers and data can be ideally designed and used, the results provide grounds for a more nuanced understanding of the institutional processes related to setting performance goals.