Educational leadership plays a crucial role in the operation and effectiveness of educational institutions. At the core of this approach, educational leaders such as school principals stand out, whose decisions and practices have direct implications on the quality of students' learning and academic success (Day, Gu, & Sammons, 2016; Machado et al., 2022; Pereira et al., 2021). The concept of the principals’ effect has surfaced as a key factor in improving student outcomes. This is particularly linked to perspectives on successful leadership (see, for instance, Leithwood et al., 2006), underscoring the idea that leadership plays a pivotal role (Eberts & Stone, 1988; Hallinger & Huber, 2012) in the development of collaborative organizational learning, structures, cultures and communities in creating a positive school environment and enhancing teaching quality (Hallinger, 2010). The literature in this field reiterates the need to investigate how leadership policies and practices are implemented in schools and their influence on learning and student results (Leithwood et al., 2006; Witziers et al., 2003). A study carried out by Flores (2022) shows that it is difficult to reconcile a culture of leadership oriented towards pedagogical issues and improving student results - which presupposes the assumption of flexibility, diversity and differentiation, both from an organizational, curricular and pedagogical point of view - with structures that are still rigid and uniform, showing the persistence of a school culture with traces of the tradition of bureaucratic centralism. Other studies conclude that in schools where principals' leadership practices are situated in the instructional and transformational perspective, there has been a positive evolution in student results (Day et al., 2011). The results of an international project on successful school principals also point to the importance of leadership values, qualities and strategies in explaining the variation found in student results (Day & Leithwood, 2007; Moos et al., 2012). Thus, this study is part of a larger research project “Assessment in Basic and Secondary Education: teachers´ practices and conceptions of internal and external assessment in Portuguese schools” funded by the Portuguese Foundation for Science and Technology (CEECIND/03157/2018) that has a strong empirical component in order to get to know the teachers’ conceptions and practices of assessment in Basic and Secondary Edu­cation and to understand to what extent the external and internal assessment influences the quality of learning and how they relate to each other. In particular, the present study aims to explore school principals' perspectives on both internal and external assessment, to understand how school principals' implement the assessment process in their schools/school clusters and to analyse the principal's perceptions of the impact of educational policies on student outcomes.

The main goal of this study is to analyse the school principals’ perceptions regarding assessment process in 16 schools/school clusters. Among these 16 schools, 4 are ranked among the 7 best public secondary schools in Portugal and 4 are ranked among the 7 secondary schools with the lowest academic results. Furthermore, the other 4 schools are classified among the 7 best basic schools in Portugal, while the remaining 4 are classified as basic schools with lower academic results. Data was collected through exploratory semi-structured interviews with 16 principals of school clusters/ schools. The interview covers six discussion topics, namely regarding the school, the leadership, conceptions of assessment, students results, educational policies, and assessment practices. The selected schools were contacted and permission was sought from the principals to conduct the interviews. The research project was approved by the Ethics Committee for Research in Social Sciences and Humanities of the University of Minho (CEICSH 134/2022) as well as authorization from the DGE to carry out the study in a school environment (Ref.ª 0803500001). Aspects related to the objectives of the study, as well as ethical issues, were clarified by the researcher before the interview took place. To analyse the data, content analysis was used in order to analyse the content of messages (Bardin, 1977), allowing to make inferences by systematically and objectively identifying the specific characteristics of a message (Esteves, 2006). Thus, analysis and coding were carried out based on the interpretation of messages through a comparison between the previous reference framework and the empirical material collected, including categories that emerged from the data. An individual analysis of each interview was carried out, followed by a cross-analysis to find response patterns and recurring themes (Huberman & Miles, 1994). For the purposes of intersubjective validation, the strategy of "checking" (Creswell, 1998) was used between the researchers involved in the analysis process to systematize the data and its interpretation.

Most principals assert that their leadership is collaborative, cultivating strong connections with key staff, teachers, and students. Concerning assessment, there is a prevailing belief among principals that it should primarily be formative, emphasizing continuous feedback. However, despite holding this perspective, principals acknowledge challenges in consistently aligning their practices with these ideals due to the pressure to achieve positive results in external evaluations. They mention working towards the preparation for end-of-cycle exams and national exams that facilitate access to higher education. Regarding external tests, a significant number of principals do not attribute much importance to them, as they are considered external assessments but lack a formal grading system. These benchmark tests are viewed as tools solely for monitoring the learning process within continuous assessment rather than providing a graded evaluation. This discourse is particularly pronounced among principals leading schools that consistently rank high, whether they are secondary or elementary institutions. In terms of educational policies, we inquired about the recent implementation of policies that have introduced more autonomy and curricular flexibility in the last five years. Principals admit they lack effective autonomy to promote increased curricular flexibility. From the principals' perspective, these changes are perceived as cosmetic and superficial, without bringing substantial benefits or alterations to the assessment process. Nevertheless, some principals have indicated having more autonomy to manage the learning and assessment process, particularly concerning the organization of time, areas of curricular autonomy, and articulation between different levels and subjects. However, principals believe that teachers are the ones who have the most influence on students' academic outcomes, in addition to their leadership practices.

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