Several countries have implemented monitoring systems where students need to take standardized tests at regular intervals. These tests may serve either a development-oriented goal that supports public trust in schools, or a more accountability-oriented perspective to increase control. Currently, the Flemish education system has no standardized testing. The idea of implementing a monitoring system is highly contentious. By means of a Delphi study with policy makers, education specialists, school governors, principals, teachers, and a student representative (n=24), we identified the characteristics of a monitoring system that would be accepted by different stakeholders. Based on these characteristics, we proposed eight scenarios for future policy development. Next, the desirability of these scenarios was assessed by each respondent. The results show that in order to gain broad social support, a focus on strengthening trust is preferred over a focus on control through such measures as avoiding the public availability of test results. In addition, other key results for the development and implementation of a system to monitor student learning outcomes are discussed.