Scarcity in public service agencies requires a prioritization of resources, and inherent to all prioritizations is a comparison of the cases. Despite the amount of research that has been conducted on the prioritization process, surprisingly little attention has been paid to the underlying comparison. Drawing on insight from the street-level bureaucracy literature, this study suggests that the administrative grouping of citizens in public service agencies influences the comparison so that the allocation of public services not only depends on a citizen’s need, but also on the needs of the other citizens assigned to the same agency. In a fixed effects analysis, based on registry data on more than 300,000 students, this study exploits the as-good-as-random assignment of students to classes within schools to analyze the influence of classroom composition on referrals to special education in Danish primary school. The result shows that students with better-performing peers are considerably more likely to be referred to special education than equally low-achieving students in lower-performing classes. This finding substantiates the argument of frame of reference effects in street-level bureaucracy and illustrates an unwarranted distributive consequence of the administrative grouping of citizens, thereby initiating a theoretical discussion of how such an influence can be mitigated.