Fundamental precondition for successful school development is the inner-school cooperation of staff. An important basis for the effective implementation of improvements is, in the long run, a positive climate, which enhances the capacity of innovation. (Bergmann & Rollett 2008). Besides the teachers’ cooperation, the collaboration between the teaching staff and further educational staff engaged in all-day-school activities (e. g. social worker, sports trainer, musicians etc) plays a decisive role in all-day schools. The mentioned staff is inhomogeneous concerning qualification and worked hours. This paper investigates the impact of the variety of employed personnel on the inner-school cooperation. Main questions are: How does it influence the quality of cooperation? Which role does the structure of personnel play? It is assumed that the following aspects of are likely to encourage or to impede cooperation: a) capacity vs. need (ratio of staff working hours and number of pupils) b) heterogeneity of professional qualifications (variety and proportional split of qualifications) c) heterogeneity concerning working hours (variety and proportional split of working hours). We investigate the impact of the mentioned aspects of human resources on cooperation and contentment on the school-level: a) climate of cooperation within both groups of staff, b) climate of cooperation between both groups of staff, c) satisfaction of the disciplinary with human resources.

Based on the empirical research on school development (e. g. Buchen & Rolff 2006) we propose hypotheses concerning the link between human resources and inner-school cooperation and derive a typology of schools by combining different aspects of human resources with indicators for successful cooperation. The StEG-survey (Studie zur Entwicklung von Ganztagsschulen, Study on the Development of All-Day Schools, Holtappels et al. 2007) aims at exploring the prerequisites for successful school development of all-day schools in Germany. Headmasters, teachers, further educational staff, pupils, parents and schools' cooperation partners were surveyed at three time points (2005, 2007 and 2009). The analyses presented here are based on the information of 339 schools that took part in the first two waves and focus on the statements of headmasters, teachers and further educational staff.

1. We assume that the quality of cooperation is rated poorer if a high proportion of staff has a low number of working hours. 2. We presume that the chance for successful cooperation increases if are homogeneous amongst employees 3. The more professionals are accustomed to structures, colleagues and given working conditions the more likely is a successful cooperation. Therefore we assume that the climate of cooperation increases over time. The results of this analysis and of our typology of schools will give some indications for further improvement in school development.