The “Safe Classroom” bill has created in Chile the need to discuss and review the way in which school coexistence is understood and measured. Although the discussion among citizens, parliamentarians and researchers has oscillated between a security approach and a democratizing approach to school coexistence, it is still pending to identify how school coexistence is conceptualized and measured in the questionnaires that accompany the national standardized test of the Educational Quality Measurement System (SIMCE). Given the above, we sought to understand this conceptualization and explore the indicators of students and parents in relation to the School Coexistence Indicator reported to each establishment. A mixed sequential qualitative (documentary analysis) and quantitative (secondary analysis of the SIMCE 2014, 2015 and 2017 databases) sequential design study was conducted. The findings show the existence of a narrow conceptualization of school coexistence linked to order, safety and discipline. For their part, the indicators for students and proxies are significantly different from each other. Recommendations are presented for public policy aimed at broadening the construct, revising the weightings, disaggregating the indicator by educational actor, and reporting the results of the evaluation by dimensions.