After analyzing various studies, we can conclude that the elements characterizing an effective school unit are leadership, teachers, and communication among school unit members, the climate of a school unit, school culture, the logistical infrastructure, the school's relationship with the local community, and the administrative system of the educational institution. The ultimate goal of this research is to detect the current organization and administration situation of secondary education units. In particular, to examine the concept of education, the school role and the concept of effective school, to identify the existing model of administration of the educational system, the organization and administration models of the school unit in which the respondents work, and furthermore the school culture level. The method adopted for the study is the classified cluster sampling method. According to this method, clusters are initially defined, which in this case are Secondary School Units. The clusters are then classified according to their characteristics, which in this case was the geographical feature: they all belonged to the North Aegean Region. In this context, 312 questionnaires were sent to all 104 secondary schools of the North Aegean (Lesvos, Chios, Samos, Ikaria, Limnos, Fourni, Oinousses, Psara, Agios Efstratios). Out of the 312, 148 were returned completed. This means a 47.44% response rate. According to the survey results, the overwhelming majority of secondary schools in the North Aegean Region does not have a secretary at the school, and the principal already has several responsibilities, while the big problem is the centralized and bureaucratic nature of the administrative organization model of the educational system, but also of the administration and organization of the school units. The nature of this model makes it incomplete, time-consuming, perfunctory, irrational, inadequate and ineffective, which means that principals and teachers do not have the flexibility to take initiatives that will improve the quality of education and teaching at the school unit they serve according to the needs of students and the local community, and based on the school's connection to the wider society and the changes that are taking place in its environment. Moreover, it was emphasized that this model, in addition to making school units more difficult to operate, also results in a misallocation of staff and consequently increased costs.

In order for educational organizations, or otherwise educational units, to accomplish their purpose, effective management is a prerequisite. The ultimate goal of this research is to examine the environment and operation of the school unit. More specifically it examines the problems of the school unit, the effectiveness of communication, the prevailing climate, the abilities of the principal and the existence of an evaluation method. The method adopted for the study is the classified cluster sampling method. In this context, 312 questionnaires were sent to all 104 secondary schools of the North Aegean (Lesvos, Chios, Samos, Ikaria, Limnos, Fourni, Oinousses, Psara, Agios Efstratios). Out of the 312, 148 were returned completed. This means a 47.44% response rate. As regards the way the school unit operates, research has shown that it does not lack cooperation among school unit members, effective leadership, adequate guidance and encouragement from teachers, or effective communication. Specifically, on the question of communication, respondents' answers show that communication between school unit members and parents as well as between the school unit and the local community is to a moderate or to small extent effective. Regarding the issue of leadership, respondents' answers indicate that almost half of the teachers believe that the principal in the school unit they serve has the necessary skills and abilities to meet the requirements of this position. Another feature of the operation of the school units involved in the survey is the lack of school evaluation.At this point it is worth pointing out that the results of the research show that the problems faced by the majority of the school units involved in the survey are, according to the respondents' answers, due to the ineffective organization of the educational system itself and consequently of the school units as well, namely the bureaucratic and centralized model, which does not provide flexibility for school units and teaching staff to take initiatives in order to enhance the educational process. 37Referring to the quality of education, Mr. Fasoulis (2001, 188) argues that quality "means the ability of the educational staff to provide effective education" and "besides that "quality" of management is also required, i.e. guidance, motivation, exploitation of resources, educational improvement; concluding that the chain reaches the top leadership of education through the requirement for quality or effective management". This again means that the educational staff should be characterized by quality management, i.e. guidance, training and motivation, through the quality and effective management of the educational unit. According to Mr. Fasouli (2001), two are the elements that we distinguish for the educational unit efficiency: teachers and leadership of the school unit. The tools that are used are culture, goals, organizational structure, environment, and primary procedure. As regards the factors that contribute to school effectiveness, the above analysis has show...

The school principal has a specific role in the school environment, which for the most part is bureaucratic. However, given the constantly changing environment in which the school operates and given the relationship between the school and the local community, the school principal needs to undertake additional responsibilities and moreover also possess specific skills in order to fulfil his or her role as a principal-leader. The ultimate research goal is to determine the purpose of leadership within the school unit. The method adopted for the study was a review of the relevant literature. In light of the present study, it is evident that in order for educational organizations, or otherwise educational units, to accomplish their purpose, effective management is a prerequisite. As regards the factors that contribute to school effectiveness, researches have shown that there is an inseparable link between school unit leadership and school effectiveness. An effective school principal-leader assists and supports teachers, while overseeing the educational work, and also encourages and promotes the involvement of teachers and parents in the decision-making process, which leads to the commitment of teachers to the school organization and increases their job satisfaction and performance. Furthermore, teachers should be able to teach all children, both those with high cognitive abilities and those with a low level of academic skills. An important role in this process plays the principal of the school. However, teachers, on the other hand, should not simply accept the principal’s vision, especially if they want to be an integral part of the process of school change. Instead, teachers should create a vision for the school together with the principal, and not just act as executors of his/her vision. Finally, four factors characterize the successful process of improving the school unit. These factors are: recognition of the improvement process by the school leadership, interaction and communication both between school members and between the school unit and the local community, the existence of a system of values, as well as cooperation between school members, and between them and society, to design and implement the selected strategies.