“The school principal’s role as a leader in teachers’ professional development: the case of public secondary education in Athens”

This research aimed to examine the role of leadership in the school environment and leadership’s contribution to the effectiveness of teachers’ professional development in the public secondary education of Athens to improve the learning process and school quality. More specifically, this study highlights the school principal’s contribution as a leader in teachers’ professional development. The choice of leadership style (education, administrative, transformational, ethical, participatory, and contingent) positively impacts teachers’ professional development. Data were collected from 180 teachers of the public secondary education of Athens, involving lower secondary schools, upper secondary vocational and general schools, excluding private and other types of schools. SPSS software was used to perform quantitative analysis of the collected data. The results showed no statistically significant correlation between teachers’ gender, skills, characteristics, and abilities. However, it was observed that there was a statistically significant correlation between age, tolerance, and rejection of educational techniques on teaching practice. The evidence from this study confirmed a direct impact of the school principal’s training on teachers’ professional development. Finally, it was con- cluded that the school principal – the leader should work as a learning manager to lead teachers in professional development and as a learning manager and an inspiration for lifelong learning.


INTRODUCTION
In the last few years, a growing interest in educational management and leadership field through various studies has arisen Knapp & Hopmann, 2017;Melissopoulos & Stravakou, 2018), highlighting the fact that leadership has a positive contribution to organizational learning and outcomes Harris & Jones, 2018). At the secondary school level, the primary responsibility for administration and organization lies with the school principal, who is required to perform the role of the leader (Kirkigianni, 2014). However, the school principal plays an essential role in educational change and effectiveness (Cheng & Townsend, 2000). School principals' roles and responsibilities include providing incentives for teachers to improve through personal skills, coordination of actions, diplomatic manipulations, and long-term experience (Green, 2001). Except for the teachers' interpersonal relations, the school principal's role has been expanding, for instance, on the effective communication with

Leadership in the field of education
A considerable amount of literature has been published on leadership and highlighted its contribution to organizational science (Belias & Koustelios, 2014). Sometimes, the term of leadership is confused with management. Several researchers, however, note that management includes elements that concern the organization and less the encouragement and commitment of people who work for . Several empirical studies have concluded that leadership is one of the most complex and widely studied constructs in the organizational sciences (Belias et al., 2015). Despite all, leadership is directly related to the management (Togas & Rekleiti, 2013;Pashiardis, 2001;Bourantas, 2005). Stogdill (1950) referred that leadership is "the process (act) of influencing the activities of an organized group in its efforts toward goal setting and goal achievement". Zaleznik (1977) referred that "Leadership requires using power to influence the thoughts and actions of other people". Hersey and Blanchard (1988) also defined leadership as "the process of influencing the activities of an individual or a group in efforts toward goal achievement in a given situation". However, leadership is one of the concepts observed that were very difficult to be defined with a general definition because of its complexity (Koech & Namusonge, 2012;Silva, 2016). Silva (2016) supported that leadership is "the process of interactive influence that occurs when, in a given context, some people accept someone as their leader to achieve common goals". Moreover, Pashiardis (2004) set leadership as "the nexus of those behaviors used with others when trying to influence their own behaviors". Saitis (2008) pointed out that leadership application depends on the leader's characteristics. Leadership behaviors and styles have an important impact on the leadership process (Brinia, 2011). For this research, Bourantas' (2005) definition of leadership is adopted. Based on Bourantas' definition (2005), leadership is the process of influencing the thinking, attitudes, and behaviors of a group of individuals from a leader to work together voluntarily and achieve common goals. Shega and Tarekegne (2018) stated that leadership has an essential role in school effectiveness and diffuses through goal setting and accomplishment. Leadership skills can be acquired through educational training (Skoulas, 1983;Zaleznik, 1989) or are innate charisma (Kirkigianni, 2014). Greece has a centrally governed and managed education system compared to other countries in Europe (OECD, 2011). The crucial challenge for education reform is school leadership. School leadership is defined by Spillane et al. (2004) as the identification, acquisition, allocation, coordination, and use of the social, material, and cultural resources necessary to establish teaching and learning conditions. School leadership has a substantial role in achieving the school's goals (Saiti & Fassoulis, 2012).

Factors that affect teachers' professional development
In the literature, there seems to be no general definition of teachers' professional development. Avalos (2011) defined teachers' professional development as "teachers learning, learning how to learn, and transforming their knowledge into practice for the benefit of their students' growth". O'Sullivan (2018) supported that teachers' professional development is an important component in the teaching and learning process and student outcomes. However, professional development presupposes the active presence of a principal (Athanasoula-Reppa, 2012). School principals shape a supportive learning environment for increasing teachers' professional development (Pashiardis, 2014). The effective school principal faces many challenges, especially creating a "culture of quality" to infiltrate into the processes and systems of the educational organization (

The impact of the principal professional development opportunitiesofessional development
The school principal's role in the teacher's professional development is very crucial and often decisive. The school principal occupies a unique position in a complex school environment and can affect the teacher's professional development (Bredeson, 2000). However, the choice of a leadership style has a significant contribution to teach-ers' professional development. Then, the question that emerges is which leadership style is the best for a school principal (Athanasoula-Reppa, 2008).
The school principal has a directional role through leadership. The school principal must choose a leadership style that is in line with each school unit's needs and the specific characteristics and abilities of the teaching staff (Papaioannou et al., 2013;Kirkigianni, 2014 In fact, contrary to the above styles, transactional leadership is based on a system of rewards and punishment (Bass, 1990). The school principal benefits from recognizing his role, while the teacher increases the chance of choice for professional development (Pashiardis, 2012).

The school principal's role and leadership in teachers' professional development
School principals and teachers play a major role in developing a school culture for professional development (Lee & Li, 2015). The school principal leads training programs, seminars, and workshops; simultaneously, he informally assesses teachers' skills. Unanswered aspects of the relationship between school leaders and teachers and its effect on professional development were investigated (Sit, 2015). Based on previous studies (Green, 2001;Leithwood & Rielh, 2003;Day, 2005), the general characteristics that school principals must acquire as leaders of the school are as follows: • creating relationships with educational staff, parents, and students; • creation and transmission of common vision and goals; • promotion of the leadership of power-sharing and allocating responsibilities; • creating a feeling of collectivity; • collaboration, understanding, and teachers' development; • personality traits.
The school principal has a consultative and guiding role in achieving professional development (Owens, 2001). School principals are responsible for shaping the conditions of the school environment for professional development, based on their special characteristics. Leithwood (2005) referred that leaders' age, gender, and education can affect their behaviors.

RESEARCH HYPOTHESES
Based on the literature review, this research proposes and attempts to test the following hypotheses:

AIMS AND METHODOLOGY
This research aimed to highlight the importance and impact of leadership in the school environment on the effectiveness of teachers' professional development to improve the learning process and school quality. Simple random sampling was used as the method of selection. The sample population consisted of teachers who work in 8 municipalities of the third public secondary education of Athens (Egaleo, Agia Varvara, Agioi Anargyroi, Ilion, Kamatero, Peristeri, Petroupoli, Haidari), involving lower secondary schools, upper secondary vocational and general schools. The questionnaire was developed and divided into four parts, including a) characteristics, skills, and abilities of a school principal, b) school factors (culture, educational work, and effectiveness) and teacher's professional development, c) the leadership role and its contribution on teachers' professional development, and d) demographic questions. All variables were measured using 5-point Likert scales (1 = totally disagree, 5 = totally agree). Data were processed, and all hypotheses were tested at the 0.05 significance level using SPSS.

Demographic data analysis
The demographic analysis of the sample characteristics (180 teachers) is presented in Table 1. Based on the results of Table 1, it is shown that teachers are well experienced and educated.

Reliability analysis
The reliability was tested with Cronbach's alpha coefficient, which is the most commonly used measure of scale reliability (Field, 2013). Table 2 presents Cronbach's alpha results for the questions below. The internal consistency, calculated with Cronbach's alpha, ranged from 0.705 to 0.915, indicating acceptable internal consistency.

Testing of hypotheses
The results of the analysis of research data through the testing of research hypotheses offered important findings. Afterward, Pearson's Chi-squared test was carried out to test the hypotheses.

Testing of hypothesis H 1
According to the results of Table 3, except the variable "Application of administrative or organizational theories in practice" (sig. = .024 < 0.05), it is concluded that there is no statistical correlation between the variables of characteristics, skills, and abilities of the school principal and teacher's gender (questions 1 and 6 with gender).
The results from Table 4 showed a statistically significant correlation between the variables of flexibility and age (sig. = .006 < 0.05), as well as between the variables "Rejection of educational techniques which are related to teaching practices" and age (sig. = .049 < 0.05). The p-value for the other characteristics, skills, and abilities is smaller than 0.05, which suggests no statistical correlation with age. In this case, the test results were not statistically significant (sig. > 0.05); therefore, hypothesis Η 1 is rejected. Overall, it is concluded that the characteristics, skills, and abilities of a school  principal as a leader are not differentiated depending on gender and age (questions 1 and 7).

Testing of hypothesis H 2
The results from Table 5 revealed a significant and strong positive correlation between the examined variables (sig. < 0.05). In this case, H 2 is confirmed, and it is obvious that the school principal's role as a leader impacts the teacher's professional development (question 3).

Testing of hypothesis H 3
The results from Table 6 revealed a statistically significant correlation of the following variables: Professional training through seminars, conferences, workshops (sig. = .000), Further education (sig. = .000) and Information and Communication Technologies (ICT) in education (sig. = .000), while for the remaining variables, no statistically significant correlations were found. Therefore, hypothesis H 3 is confirmed and showed that the school

Testing of hypothesis H 5
According to the results of Table 8 for hypothesis H 5 , a statistically significant correlation between all the variables of school factors and teacher's professional development is showed (sig. < 0.05). Therefore, H 5 is confirmed that school factors (culture, educational work, and effectiveness) affect the teacher's professional development (question 3). The results from Table 9 showed a statistically significant association was between the variables. More specifically, the school principal as a learning manager (sig. = .000), as a specialist on teaching, learning and school education (sig. = .000), as exemplary (sig. = .000) and instructor on teaching and learning issues (sig. = .000) affects teacher's professional development. Therefore, H 6 is confirmed, and it is concluded that the leadership role chosen by the school principal is not intricately linked to the teacher's professional development (questions 3 and 4). From the results of Table 10, a statistically significant correlation between the variables mentioned above was observed. Specifically, educational leadership (sig. = .000), managerial leadership (sig. = .000), personal changes and improvements for total changes both in teachers and the school unit (sig. = .000), moral leadership (sig. = .000), participative leadership (sig. = .000) and contingent leadership (sig. = .003) affect teacher's professional development. Therefore, hypothesis H 7 is confirmed (questions 3 and 5). It is concluded that leadership styles that are chosen by the school principal can affect the teacher's professional development.

CONCLUSION
Teachers' professional development has been an increasingly important issue in the field of education. The role and contribution of the school principal-leader are some of the most crucial and determinant factors in teachers' professional development. School principals' leadership is a crucial factor for teachers' professional development as a prerequisite for establishing and success of a learning community (Bredeson, 2000). Principals need to be "agents of change" within their school units (Romay et al., 2016) and lead change processes.
Initially, the results from the first hypothesis showed that depending on gender or age, characteristics, skills, and abilities of the school principal that make up the leader of a school unit are not differentiated. The second hypothesis revealed a statistically significant correlation between the school principal's role as a leader and teacher's professional development. The results of this study also reflect the direct impact of principals' training on teachers' professional development. Principals' leadership practices are considered an important element for teach-

N of valid cases
The school principal as leader follows effective educational leadership strategies, focusing on standards provision, teacher education, teacher's monitoring, and exchange of views (educational leadership) *To what extent do you think a school principal-leader contributes to teachers' professional development? .000 .000 .000 170 The school principal-leader exercises control and supervision to improve teachers and school unit (managerial leadership) * To what extent do you think a school principal-leader contributes to teachers' professional development?
.000 .000 .000 170 The school principal-leader encourages personal changes and improvements for total changes both in teachers and the school unit. He/she also creates a climate of mutual appreciation * To what extent do you think a school principal-leader contributes to teachers' professional development?
.000 .000 .000 171 The school principal-leader exercises power, and leadership stems from what he/she considers moral or not (moral leadership) * To what extent do you think a school principal-leader contributes to teachers' professional development?
.000 .000 .000 170 The school principal-leader is moving in a context of cooperation and participation with teachers through dialogue in educational decision making, by taking an active role from teachers' perspective (participative leadership) * To what extent do you think that a school principal-leader contributes to teachers' professional development?
.000 .001 .000 171 The school principal-leader adapts and applies a leadership style to the right situation (contingent leadership) * To what extent do you think that a school principal-leader contributes to teachers' professional development?
The results showed that these variables affect teachers' professional development. The role of leadership is decisive in teachers' professional development, based on the school principal's experience of the subject and knowledge. Also, the research revealed an important correlation between professional development and leadership style. The role of the school principal has a substantial impact through leadership in teacher's professional development.