Like many European countries (Federičová, 2021), Germany’s education system is grappling with a significant teacher shortage, a crisis that poses challenges for maintaining educational quality in primary schools (Seeliger & Lindqvist, 2023). This shortage has prompted policymakers and administrators to adopt flexible but potentially contentious staffing measures. Among the most prevalent measures are assigning teachers to teach outside their trained subject areas (e.g., music teachers teaching mathematics), deploying teachers to educational levels for which they were not originally trained (e.g., secondary school teachers in primary schools), and recruiting individuals through alternative certification pathways. While these approaches aim to alleviate immediate staffing shortages, they raise concerns about their potential impact on teaching quality and student achievement.

Our study seeks to address these pivotal questions by investigating the educational effectiveness of each measure. Specifically, we examine whether teaching quality and student performance vary when comparing the three strategies to instruction deliver by traditionally certified primary school teachers within their trained subject areas.

Based on the framework of Utilization-of-Learning-Opportunities models, this study posits that teacher qualifications and professional competencies, developed through traditional teacher education programs, are pivotal in promoting teaching quality and shaping student outcomes (Seidel, 2024). These competencies equip teachers to manage classrooms effectively, provide constructive support, and foster cognitive activation— core dimensions of teaching quality widely acknowledged as essential drivers of student learning outcomes (Praetorius et al., 2018; Praetorius et al., 2020).

It can be assumed that teachers will are most effective in applying their competences within schools or areas for which they have received training. For example, teaching outside one’s trained subject area or school track may hinder the application of professional competencies, potentially reducing both teaching quality and student outcomes. While extensive research underscores the critical role of teacher qualifications in enhancing teaching quality and fostering student learning (Kunter et al., 2013; Lee, 2018), the impact of alignment between teaching assignments (e.g., subject-appropriate, school-track-appropriate, or traditionally certified) and its influence on teaching quality and student achievement remains underexplored.

Moreover, most studies have focused on secondary education, where subject specialization is more pronounced, leaving a substantial gap in understanding how these dynamics function in primary schools. In primary education, generalist teaching is more common but equally reliant on the alignment between teacher qualifications and teaching assignments. Our study addresses this gap by investigating whether teaching assignments aligned with a teacher’s qualifications contribute to higher teaching quality and improved student outcomes in primary education.

Our study focuses on three objectives. First, it examines effects of flexible staffing policies on teaching quality and student outcomes. Second, it evaluates the effectiveness of alternative certification programs in maintaining educational quality. Third, it strives to provide evidence-based insights to inform policymakers on optimizing staffing strategies in education. Drawing on large-scale, representative data from a national assessment study of primary school students in Germany, the study provides a comprehensive analysis of the impact of these staffing strategies.

The findings aim to contribute to the ongoing discourse on balancing flexibility in teacher assignments with the need to maintain high educational standards. Understanding whether flexible staffing measures, such as employing alternatively certified teachers or implementing out-of-field teaching, compromise teaching quality and student achievement is crucial for designing effective interventions. Additionally, the study highlights the broader implications of these measures for teacher professionalism, emphasizing the need to develop robust training programs that equip educators to navigate the diverse demands of contemporary classrooms.

This study draws on data from the “IQB Trends in Student Achievement 2021”, a representative assessment of fourth-grade students and their teachers in Germany. The dataset includes 26,844 students and 1,738 teachers, providing detailed information on teacher qualifications, teaching quality, and student performance in mathematics and German, making it well-suited for analyzing the effects of flexible staffing measures on educational outcomes. Teacher background, teaching quality, and student performance were assessed using validated instruments. Teacher data were collected via questionnaires covering demographics (age, gender), job experience (total years teaching years, semesters teaching the tested class), academic qualifications (degree subjects, certification levels), and participation in alternative certification programs. Teaching quality was measured through student surveys based on the three-dimensional model of instructional quality (Klieme et al., 2009), encompassing classroom management (e.g., lessons free from disruptions; 6 items, Cronbach’s α: .88–.90), constructive support (e.g., teacher support and motivation; 7 items, Cronbach’s α: .87–.88), and cognitive activation (e.g., tasks fostering deep understanding; 6–9 items, Cronbach’s α: .67–.76). Student performance was measured using standardized tests in German (reading, listening, orthography) and mathematics (five curricular domains), employing a multiple-matrix design to ensure feasibility. All measures were calibrated within the national assessment framework (Stanat et al., 2022). The analyses compare teaching quality and student outcomes across three groups: teachers assigned to subject-out-of-field, school-track-out-of-field, and those recruited through alternative certification pathways, relative to traditionally certified primary school teachers teaching within their trained subject areas. To address selection bias and account for the hierarchical data structure (students nested within classrooms, classrooms within schools), the study employs Multilevel Propensity Score Matching (MLPSM; Keele et al., 2020) and multilevel regression analyses. MLPSM creates comparable groups of teachers and students by balancing observed covariates at the student level (e.g., gender, socioeconomic status, migration background, home resources) and classroom level (e.g., teacher experience, qualification type). This approach enables robust causal inferences. Following matching, multilevel regression analyses estimate the effects of teacher assignment types on teaching quality and student performance, controlling for student-level variables (e.g., gender, socioeconomic status, migration background) and teacher-level variables (e.g., years of experience).

The study examined differences in teaching quality and fourth graders’ educational achievement across various teacher groups. First, no significant differences were found in teaching quality or student performance in German and mathematics between teachers assigned to teach within their trained subject areas and those teaching out-of-field. Second, teaching quality was rated similarly high for teachers trained for primary education and those qualified for other school tracks. However, students taught by school-track-out-of-field teachers performed significantly worse in orthography (β = -0.17) and listening comprehension (β = -0.14), while no differences were observed in mathematics performance. Finally, teachers entering through alternative certification pathways demonstrated teaching quality and student outcomes comparable to traditionally certified teachers, with no significant differences in any of the measured domains. The findings provide valuable insights into mitigating teacher shortages while maintaining educational quality. Flexible staffing strategies, such as assigning teachers to teach out-of-field or hiring alternatively certified teachers, generally do not undermine teaching quality or student achievement. However, the lower outcomes in orthography and listening comprehension among students taught by school-track-out-of-field teachers highlight the importance of aligning teaching assignments with teacher qualifications. These findings emphasize the need for targeted interventions, such as professional development and mentoring programs, to support school-track-out-of-field teachers and address these specific disparities. Ultimately, the study underscores the importance of balancing staffing flexibility with policies that maintain high educational standards. By investing in teacher education and support systems, educational leaders can address teachers’ shortages while ensuring equitable and effective learning opportunities for all students.

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