This paper examines a professional development program for school leadership and school development combining multiple interventions and their quality and benefits. The longitudinal mixed methods study analyses the effect on school leadership, school development and school quality in schools in challenging circumstances. It is based on data from an accompanying study of a program aimed at supporting schools in disadvantaged areas, providing school principals from schools in low socio-economic environments with various interventions to aid in the further development of their schools.

The study builds on research on school effectiveness and school improvement, especially regarding schools in challenging circumstances in terms of school turnaround and the role of school leadership.

Due to their location and the composition of the student body, schools in challenging circumstances face more difficult conditions. These schools typically have a high proportion of students from underprivileged family backgrounds, often measured by their parents' education levels and financial circumstances. These poorer socio-economic conditions are frequently associated with the need for special compensatory efforts by the school. However, characterizing a school as a being in a disadvantaged area does not automatically imply diminished school quality (Racherbäumer & van Ackeren, 2015). Some schools may face greater challenges for various reasons, including lower graduation rates or poorer academic performance (Holtappels et al., 2017). Moreover, there can be a cumulative effect of dysfunctional organizational characteristics (composition effect), which can lead to significantly lower school quality and/or more difficult school development processes. In other words, stressors not only affect the current quality of the school but also hinder its progress and improvement (Author, 2018, 2020). As a result, quality characteristics can differ. These schools need external support. The necessary additional support from the system can be provided within the framework of professionalization and advisory services. The range of support measures can vary, including leadership development through training and further education, process consulting and coaching offers, and providing additional resources in the form of time, equipment, and funding.

School leadership also plays an important role not only in school development and building school development capacities but also in accessing external resources and moderating and mediating external interventions. The importance of school leadership for school effectiveness (see, among others, Fend 1987, 1998; Rutter et al. 1979; Sammons et al. 1995) and school improvement, aimed at continuous enhancement of schools (see, among others, Fullan 1988, 1991, 1992; Leithwood & Montgomery 1986; Schratz 1998), has been well-established since the 1980s (Author 1997, 1999a,b,c, 2010a,b, 2011a, 2012, 2016a,b). Consequently, the question of effective and successful actions by educational leaders, especially school principals, has become one of the central topics in educational discussions. There is now broad agreement on the necessity and significance of corresponding professionalization and qualification opportunities. In this sense, leadership development is closely related to the development of the quality of schools.

This five-year longitudinal sequential explanative mixed methods study is based on a sample of around 150 schools in challenging circumstances from a German state. Over a three-year period, half of the schools experienced additional measures to professionalize school leadership (e.g., coaching of school leaders, continuous professional development program) and support for school development (additional financial resources, process consultancy for school development activities). The qualitative analysis includes school documents (e.g., school strategy documents), semi-structured interviews with different actors in the schools (at baseline, after three years), and protocols of coaches and school development consultants. Qualitative data are analyzed using qualitative content analysis (Mayring, 2015). For the quantitative analysis, six questionnaires with staff and school administrators are conducted - three on the work situation, three on the various interventions. Statistical data from government agencies and student achievement data are also analyzed. In addition to a descriptive evaluation of the quality assessments of staff and school leaders, regression analyses are conducted to examine the impact of specific program components on selected school quality characteristics during the program period. As the program was implemented at the school level, the analyses were conducted accordingly. Through a comparison group design, it is possible to compare the changes in project and comparison schools and to relate them to the program interventions. To measure the changes in the schools using questionnaire data of the survey on the work situation, the effect size Cohen's d (Cohen, 1988) was calculated, which refers to the practical relevance of the results. The paper focuses on the support measures, examining both the processes and the outcomes. Therefore, the paper investigates the quality of the program components in terms of the assessment of the involved actors and provides an overview on the topics, objectives, processes, and impact particularly of school leadership coaching and school development consultancy on school quality and its changes.

The findings show the very positive assessment of the program’s quality and benefits and its positive consequences on the school’s quality. The regression analyses demonstrate that positively perceived outcome qualities of the interventions are associated with improvements in numerous dimensions of school quality (e.g., cooperative leadership). Effect sizes show that most schools involved in the program developed better over time than the comparison schools. The analyses of interviews and protocols on school leadership coaching and school development consultancy reveal numerous benefits of their activities in organizational, personnel, and instructional development. For example: Coaching primarily addresses aspects of self and personnel management and aids in self-management by allowing leaders to reflect on challenging situations, develop problem-solving strategies, and gain a better understanding of their values and role. Successful implementation of coaching and school development consultancy shares several common features. The expertise and competence of the coach and the consultant play a vital role in the effectiveness of the coaching and consultation process. Equally important is the design of the framework conditions surrounding the measures and adequate structural resources. Additionally, ensuring a good fit between the coach/consultant and the coachee/school is of importance to ensure a successful process. Overall, the findings provide evidence for the effectiveness of school development programs on school leadership and school improvement. The results indicate that intervention strategies should be tailored to the individual school's circumstances, needs, and challenges, ensuring they fit precisely into the school's specific context. For project initiators and decision-makers, this means providing a framework that is individually adapted by each participating school to its unique context. This is a prerequisite for sustainable and effective transfer of knowledge into school development processes. The interventions will be discussed in terms of their effects and the necessary conditions for successful implementation, along with their practical implications.

Author 1997, 1999a,b,c, 2010a,b, 2011a, 2012, 2016a,b, 2018, 2020 Cohen, J. (1988). Statistical Power Analysis for the Behavioral Sciences (2nd ed.). Routledge. https://doi.org/10.4324/9780203771587 Fend, H. (1987). „Gute Schulen – schlechte Schulen“ – Die einzelne Schule als pädagogische Handlungseinheit. In U. Steffens & T. Bargel (Hrsg.), Erkundungen zur Wirksamkeit und Qualität von Schule (Beiträge aus dem Arbeitskreis Qualität von Schule, Heft 1 (S. 55 – 80). Hessisches Institut für Bildungsplanung und Schulentwicklung. Fend, H. (1998). Qualität im Bildungswesen. Schulforschung zu Systembedingungen, Schulprofilen und Lehrerleistung. Weinheim: Juventa. Fullan, M. (1988). What’s worth fighting for in the principalship. Ontario Public School Teachers’ Federation. Fullan, M. (1991). The new meaning of educational change. Cassell. Fullan, M. (1992). Successful school improvement. Open University Press. Holtappels, H. G., Webs, T., Kamarianakis, E., & Ackeren, I. van (2017). Schulen in herausfordernden Problemlagen–Typologien, Forschungsstand und Schulentwicklungsstrategien. In V. Manitius & P. Dobbelstein (Ed./Hrsg.), Schulentwicklungsarbeit in herausfordernden Lagen (S. 17 – 35). Waxmann. Leithwood, K. A., & Montgomery, D. J. (1986). Improving Principal Effectiveness: The principal profile. Toronto: OISE Press. Mayring, P. (2015). Qualitative Inhaltsanalyse. Grundlagen und Techniken. Weinheim: Beltz. Racherbäumer, K., & Ackeren, I. van (2015). Was ist eine (gute) Schule in schwieriger Lage? Befunde einer Studie im kontrastiven Fallstudiendesign an Schulen in der Metropolregion Rhein-Ruhr. In L. Fölker, T. Hertel & N. Pfaff (Hrsg.), Brennpunkt(-) Schule. Zum Verhältnis von Schule, Bildung und urbaner Segregation (S. 189 – 20). Verlag Barbara Budrich. Rutter, M., Maughan, B., Mortimore, P., & Ouston, J. (1979). Fifteen thousand hours. London: Open Books. Sammons, P., Hillman, J., A., & Mortimore, P. (1995). Key Characteristics of Effective Schools: A Review of School Effectiveness Research. Institute of Education, University of London, and Office for Standards in Education. Schratz, M. (1998). Schulleitung als change agent: Vom Verwalten zum Gestalten von Schule. In H. Altrichter, W. Schley & M. Schratz (Hrsg.), Handbuch zur Schulentwicklung. StudienVerlag, S. 160-189.