Leadership and curriculum innovation through semesterization: a case study from Portugal

Introduction: The organization of school time plays a decisive role in shaping teaching practices, student learning, and school culture. In Portugal, semesterization has emerged as an alternative to the traditional trimester system, aiming to improve curriculum coherence and pedagogical depth. This study examines how semesterization was interpreted and implemented in a public lower secondary school in Madeira, and how educators perceived its impact on organizational functioning and teaching practices. Recent scholarship highlights that time-use reforms such as semesterization are more likely to succeed when mediated by adaptive and distributed leadership and supported by coherent policy.

Methods: A qualitative-dominant mixed-methods case study design was adopted. Data were collected through semi-structured interviews with school leaders and an online questionnaire completed by 41 teachers from different subject areas. The qualitative component was analyzed using thematic content analysis, identifying patterns related to leadership, curriculum organization, pedagogical adaptation, and assessment practices. Descriptive statistics from the questionnaire were used to complement qualitative insights, providing an overview of broader staff perceptions.

Results: Participants perceived that semesterization contributed to a more coherent distribution of teaching time, supported thematic planning, and facilitated a steadier pedagogical rhythm for both teachers and students. Teachers described enhanced opportunities for interdisciplinary collaboration, more intentional curriculum mapping, and increased space for formative assessment. A majority also reported positive effects on student well-being. However, challenges were noted, including the substantial effort required to redesign planning tools, persistent bureaucratic demands, and concerns about achieving consistency in assessment practices across semesters. Teachers also highlighted increased workload during reporting periods, particularly in relation to mandatory mid-semester qualitative feedback.

Discussion: The findings suggest that semesterization can act as a lever for school-wide innovation when supported by distributed leadership, collaborative planning structures, and clear communication. At the same time, the reform’s success depends on system-level coherence and adequate institutional support during periods of transition.

Conclusion: Semesterization represents not merely a scheduling adjustment but a strategic rethinking of time as an organizational and pedagogical resource. The case offers transferable insights for education systems aiming to build more coherent, equitable, and learner-centered environments.

1 Introduction

The organization of school time is not merely a logistical concern but a foundational dimension of educational systems, one that significantly shapes teaching practices, learning outcomes, and the overall culture of schooling. The structure of the academic calendar reflects broader pedagogical orientations and sociocultural values, influencing both the pace and the depth of student learning (OECD, 2019). As global educational discourse increasingly shifts toward equity, personalization, and innovation, the strategic use of time has become a central focus for educational leaders, supported by research emphasizing the links between temporal organization, well-being, and instructional quality (Benade, 2017; Darling-Hammond et al., 2020). Importantly, recent scholarship stresses that time-use reforms succeed only when supported by coherent leadership and collaborative school cultures (Fullan, 2021; Leithwood et al., 2020a,b; OECD, 2023).

Traditional models, such as the trimester-based calendar still common in Portugal, are being questioned for their tendency to fragment the curriculum, compress assessment cycles, and restrict opportunities for interdisciplinary and inquiry-based learning. Empirical and policy analyses document these limitations and the benefits of extended, coherent instructional periods for deeper learning and assessment for learning (Drake and Reid, 2010; European Commission, 2022; OECD, 2023). Alternative models, including block schedules, modular timetables, and semester-based calendars, are thus gaining attention as frameworks that can enhance curricular coherence and promote richer instructional experiences.

Semesterization, in particular, has emerged as a promising framework for rethinking school organization. By dividing the academic year into two extended instructional periods, this model enables more deliberate curriculum pacing, facilitates cross-disciplinary collaboration, and supports formative assessment practices, especially in science education, where conceptual continuity and inquiry are essential (Aronson et al., 1999; Drake and Reid, 2010). However, unlocking these benefits depends on leadership capable of aligning organizational structures with pedagogical intent, cultivating shared vision, and supporting teacher capacity for change (Fullan, 2007, 2021; Robinson et al., 2009).

In Portugal, recent educational reforms have gradually expanded curricular autonomy, culminating in Decree-Law No. 55/2018, which formalized flexibility in instructional design and encouraged innovation aligned with local educational projects. Within this national landscape, the Autonomous Region of Madeira has used its governance autonomy to pioneer calendar reorganizations, including the introduction of semesterization in selected schools, creating a relevant policy setting for examining leadership-mediated reform.

This study examines one such case: a public lower secondary school in Madeira that transitioned from a trimester to semesterization beginning in the 2019/2020 school year. Through a qualitative case study methodology, it explores how this reorganization of school time influenced leadership strategies, curriculum planning, instructional practices, and school-wide collaboration. Guided by a qualitative-dominant mixed-methods case study using a convergent parallel logic, we consider points of convergence and divergence between leaders’ accounts and teacher survey patterns (Creswell and Plano Clark, 2018). The integration of interview and survey data allows for the identification of convergent and divergent perspectives across stakeholder groups.

The significance of this research lies in three interrelated contributions. First, it offers empirical insights into a reform area - calendar restructuring - that remains underexamined in international literature. Second, it highlights the central role of educational leadership in mediating structural innovation, particularly in contexts of increased school autonomy. Third, it reframes school time as a strategic pedagogical and organizational resource, rather than a neutral administrative parameter.

The core research question guiding this investigation is: How does semesterization influence school organization, leadership, and teaching practices in a public lower secondary school in Madeira, Portugal? In answering this question, the study contributes to the global discourse on educational leadership, instructional time management, and school innovation, particularly within the context of science education and interdisciplinary reform.

2 Educational policy and school autonomy in Portugal

The evolution of educational governance in Portugal since the mid-1970s reflects a gradual but deliberate move from centralization to autonomy. Following the 1974 Carnation Revolution, the Portuguese education system underwent significant democratization, culminating in the 1986 Basic Law of the Education System (Law No. 46/86), which affirmed education as a universal right and introduced principles of school democratization and community participation.

In the decades that followed, subsequent legislation - including Decree-Laws No. 43/89, 172/91, and 115-A/98 - paved the way for schools to articulate their own Educational Projects, enabling localized responses to curricular and organizational needs. Despite these developments, autonomy was often limited by centralized oversight, prescriptive curricular structures, and insufficient investment in leadership capacity (Afonso, 2016), a challenge that mirrors broader international concerns about the gap between structural autonomy and schools’ practical capacity to enact it effectively (Fullan, 2021; OECD, 2023).

Significant reform emerged with Decree-Law No. 75/2008 (revised by Decree-Law No. 137/2012), which restructured school leadership by replacing traditional collegial models with a more managerial, principal-led governance system. This reform aimed to improve administrative efficiency and accountability but also provoked criticism regarding the erosion of democratic participation and teacher agency in decision-making processes (Barroso, 2005). These dynamics mirror broader international discussions on balancing managerial efficiency with participatory leadership cultures (Hall and Hord, 2015; Leithwood and Sun, 2012).

The most transformative development in recent years is represented by the 2018 legislative package, particularly Decree-Law No. 55/2018, which redefined curriculum organization and formalized the notion of curricular flexibility. This reform permits schools to manage up to 25% of instructional time according to their own educational project and local context. Key strategies promoted under this framework include interdisciplinary learning, differentiated instruction, and autonomy in defining teaching rhythms, opening new possibilities for calendar innovations such as semesterization. The policy strengthened the expectation that schools operate as adaptive organizations capable of aligning instructional time with pedagogical goals (European Commission, 2022; OECD, 2019).

In the Autonomous Region of Madeira, this national policy intersects with region-specific legislation. Madeira’s Decree-Laws No. 4/2000/M and No. 21/2006/M, along with Ordinances No. 471/2019 and No. 313/2022, have allowed public schools to reorganize their calendars around pedagogical criteria. These regulations position Madeira as a leading case in experimenting with structural reforms that link time management with curriculum and well-being. Madeira thus illustrates how regional autonomy can serve as a driver for leadership-led reform.

The move toward semesterization in Madeira must also be seen within the broader international discourse on school autonomy. According to the OECD (2020), autonomy in curriculum and assessment is positively associated with student outcomes, particularly when accompanied by professional accountability and instructional leadership. However, autonomy without adequate support structures can exacerbate inequality between schools with varying levels of organizational capacity. The case of Madeira aligns with comparative evidence suggesting that autonomy produces innovation only when schools possess strong leadership and collaborative capacity to enact policy flexibly yet coherently (Fullan, 2021; OECD, 2023).

In summary, Portugal’s evolving policy landscape has created meaningful space for experimentation with time-use, curriculum design, and instructional autonomy. The case of Madeira demonstrates how regional initiatives can operationalize national flexibility, using temporal reorganization to foster innovation at the school level. Beyond the Portuguese context, this case offers transferable insights for other education systems seeking to balance decentralization with coherence, showing how leadership and policy alignment can transform autonomy into genuine pedagogical innovation. Yet, the effectiveness of such reforms ultimately depends on leadership capacity, collaborative cultures, and policy coherence that align autonomy with equity and professional learning.

3 Curriculum flexibility and the role of school leadership

Curricular flexibility has become a central concern in contemporary educational reform, especially in systems striving to promote inclusive, context-sensitive, and future-oriented learning. It reflects an effort to reconcile national standards with the need for local adaptation, interdisciplinary integration, and more meaningful student engagement. International studies highlight that such flexibility is associated with higher professional trust, stronger teacher agency, and improved curricular coherence (OECD, 2023; Sahlberg, 2016).

In Portugal, this flexibility was formally introduced through the Autonomy and Curricular Flexibility framework, established by Decree-Law No. 55/2018 of July 6, which redefined the national curriculum and opened space for schools to shape learning paths tailored to their specific educational projects. This legal framework allows schools to manage a portion of instructional time with autonomy and encourages project-based learning, interdisciplinary integration, and active methodologies. While the policy enables such transformations, its enactment depends heavily on local leadership capacity and school culture. The success of curricular flexibility thus hinges on how leaders mobilize professional communities and align organizational routines with pedagogical purpose (Fullan, 2021; Harris and Jones, 2015).

Educational leadership plays a central role in translating curricular policy into pedagogical action. The literature highlights several leadership models that can support this transition. Transformational leadership emphasizes the articulation of a shared vision and the mobilization of school communities around common goals. Instructional leadership focuses on the quality and coherence of teaching practices, emphasizing curriculum alignment, assessment literacy, and instructional improvement. Meanwhile, distributed leadership values collaborative decision-making and recognizes the collective expertise of educators within schools (Robinson et al., 2009; Spillane, 2006). Recent meta-analyses show that the most effective schools combine these dimensions to foster coherence and innovation (Leithwood et al., 2020b; Robinson, 2011).

The reorganization of school time, particularly through semesterization, demands leadership capable of navigating complex pedagogical, organizational, and cultural changes. Transformational, instructional, and distributed leadership styles become particularly relevant, as they shape how schools interpret reform, mobilize staff, and balance innovation with curricular coherence (Leithwood et al., 2020a,b; Spillane, 2006). The role of leadership is therefore pivotal in ensuring that structural autonomy leads to meaningful educational practices. In this regard, time-use reforms function as both managerial and pedagogical challenges, requiring leaders to integrate scheduling innovation with professional learning and shared inquiry (Fullan, 2021).

Successful curriculum flexibility also depends on teachers’ professional autonomy and their capacity to design meaningful, context-relevant learning experiences. However, these opportunities bring new demands: collaborative planning, curriculum mapping, and cross-disciplinary alignment become essential. International evidence reinforces that without leadership structures that protect time for collaboration and reflection, the potential of flexibility remains underrealized (Hargreaves and O’Connor, 2018).

Policy enactment literature reminds us that local implementation of reform is never linear. As Ball et al. (2012) argue, school leaders act as mediators between abstract policy frameworks and situated school realities. They must interpret and adapt national directives in ways that make sense for their communities, staff capabilities, and student profiles. The Portuguese and Madeiran contexts therefore exemplify the broader global challenge of turning autonomy into agency, ensuring that decentralization empowers innovation rather than reproducing inequality.

In this context, the role of school leadership is not confined to compliance or management but becomes deeply pedagogical, concerned with cultivating a shared vision of learning, building professional capacity, and ensuring that organizational structures align with educational values. The transition to semesterization provides a compelling case through which to explore how school leadership responds to reform opportunities and challenges, particularly in navigating the tensions between flexibility, equity, and coherence. This study contributes to this debate by illustrating how school-level leadership can transform temporal reorganization into a sustained professional learning strategy, an insight relevant beyond the Portuguese context.

By exploring these dynamics, the present study aims to deepen understanding of how curriculum flexibility is locally enacted and how school leadership mediates structural reforms such as semesterization. Particular attention is given to how such models affect curriculum planning, pedagogical collaboration, and interdisciplinary opportunities, including in science education, within the broader agenda of learner-centered schooling. Ultimately, the analysis offers lessons of international transferability for systems seeking to connect leadership development, curricular autonomy, and school innovation.

4 Methodology

This study employed a qualitative-dominant mixed-methods case study design, aimed at investigating how the implementation of a semester-based school calendar reshapes leadership practices, curriculum organization, and teaching methodologies within a public-school context. A convergent parallel design (Creswell and Plano Clark, 2018) was adopted, whereby qualitative and quantitative data were collected concurrently, analyzed separately, and then integrated for interpretation. The case study methodology is especially appropriate for educational research that seeks to explore complex social processes in depth and within their natural settings (Creswell, 2014; Stake, 1995; Yin, 2018). Focusing on a single school in the Autonomous Region of Madeira, Portugal, that has actively engaged with curricular reform, the study provides a nuanced and context-sensitive account of a reform still underexplored in both national and international literature.

4.1 Research design

This study adopted a qualitative-dominant mixed-methods case study approach (Stake, 1995; Yin, 2018) to investigate how semesterization reform was interpreted and implemented within a specific public school context. The research aimed to capture the lived experiences, perceptions, and institutional responses of school leaders and teachers. The combination of qualitative and quantitative strands allowed for triangulation and complementarity, strengthening both descriptive depth and interpretive validity (Denzin, 2012; Tashakkori and Teddlie, 2010). Methodological triangulation (Denzin, 2012) was employed through the combination of semi-structured interviews and a teacher questionnaire, enhancing the depth and trustworthiness of the findings. The choice of a qualitative-dominant orientation reflects the exploratory and interpretive nature of the research objectives, with quantitative data serving to document broader tendencies and reinforce descriptive claims.

The inquiry was guided by the central research question: How does the semester-based school calendar influence school organization, leadership, and teaching practices in a public lower secondary school in Madeira, Portugal?

To address this question, the study pursued two main objectives: (i) To examine how school leadership and governance structures respond to the demands and opportunities presented by semesterization; (ii) To analyze the pedagogical implications and perceived challenges of semesterization from the perspective of both teachers and school leaders.

This design also sought to identify areas of convergence and divergence between qualitative and quantitative findings, offering a more comprehensive account of the reform’s dynamics.

4.2 Site selection

The research was conducted in a public lower secondary school serving grades 5 through 9, located in the Autonomous Region of Madeira. This school was deliberately chosen based on its early adoption of semesterization during the 2019/2020 academic year and its reputation for embracing educational innovation. The site also presented logistical advantages in terms of accessibility and openness to research collaboration. With approximately 600 students and 70 teachers, the school is characterized by an active leadership team and a longstanding involvement in regional pilot programs focused on curriculum flexibility. As an “early adopter” of semesterization, the school represents a critical case (Yin, 2018) for understanding how leadership mediates reform in a semi-autonomous policy environment. The case selection therefore aligns with theoretical sampling principles, enabling in-depth examination of reform processes where they were most actively developed.

4.3 Participants and sampling

Participants were selected through purposive sampling, a strategy that privileges relevance over representativeness in qualitative inquiry. The intention was to engage individuals who had firsthand knowledge and experience of the reform’s implementation and its daily effects on school life.

Participants included two school leaders - the President of the Executive Council and the President of the Educational Community Council - who were directly responsible for coordinating and legitimizing the semesterization process. The decision to interview only these two leaders is explicitly justified: in the Madeiran governance structure, these roles jointly encompass the full scope of strategic, operational, and community leadership relevant to the implementation of semesterization. They constitute the only positions with formal authority and oversight across curriculum management, organizational planning, and stakeholder engagement, making them uniquely positioned to provide comprehensive accounts of the reform.

In addition, 41 teachers representing diverse disciplinary areas (e.g., humanities, natural sciences, mathematics, languages, and arts) completed a comprehensive online questionnaire. The inclusion of a teacher survey with both Likert-type and open-ended items provided a quantitative complement that enabled descriptive profiling and pattern detection within the broader qualitative narrative. This participant diversity ensured the collection of rich, multi-perspective data on the organizational and pedagogical impacts of the reform.

4.4 Data collection

To gain a multi-layered understanding of the semesterization process, the study relied on two complementary data collection instruments: semi-structured interviews and an online questionnaire.

Semi-structured interviews were conducted with the two school leaders, each lasting between 60 and 75 min. These interviews followed an open thematic guide that included topics such as institutional planning, leadership philosophy, communication strategies, teacher collaboration, and the integration of new evaluation practices. To further clarify the scope and structure of the interviews, examples of guiding questions include: “How did the leadership team prepare the school for the transition to semesterization?,” “What organizational challenges emerged during the first year of implementation?,” “In what ways did the new calendar structure influence interdisciplinary coordination?,” and “What strategies were implemented to support teachers’ adjustment to new assessment routines?.”

The interviews were recorded, transcribed verbatim, anonymized, and subsequently coded for thematic content analysis.

The online questionnaire was disseminated to the school’s teaching staff using Google Forms. It consisted of 20 items, combining 15 Likert-type questions with 5 open-ended prompts. The survey explored perceptions of curriculum organization, interdisciplinary collaboration, assessment practices, professional workload, and the overall impact of semesterization on pedagogical routines and teacher well-being. A total of 41 out of 70 teachers responded, yielding a participation rate of 58.6%.

To strengthen the methodological transparency of the quantitative component, additional detail is provided regarding the construction, validation, and refinement of the questionnaire. The instrument was developed from the study’s analytical framework and informed by the literature on leadership, curriculum flexibility, and time-use reforms, including work by Fullan, Leithwood, and the OECD. Particular attention was given to ensuring that the items captured teachers’ perceptions across organizational, pedagogical, and assessment-related dimensions of semesterization.

Before dissemination, the questionnaire underwent a process of content validation. The supervising researcher and a senior academic in educational leadership reviewed the items for clarity, conceptual coherence, and alignment with the research questions. Their feedback informed several refinements to the wording and internal structure of the instrument. To further ensure clarity and usability, the questionnaire was piloted with three teachers, whose comments led to minor adjustments related to phrasing and response options.

As the quantitative component of the study was descriptive and exploratory in nature, and given the modest sample size, no inferential statistical analyses were conducted. Instead, reliability was supported through careful item construction, expert validation, and piloting, which together helped ensure that the instrument was internally coherent and fit for purpose.

The combination of this questionnaire with the semi-structured interviews enabled a layered understanding of the reform, capturing both the macro-level planning perspectives of school leaders and the micro-level experiences of classroom practitioners.

4.5 Data analysis

A mixed-methods analytic strategy was employed, integrating qualitative and quantitative strands in a convergent manner. The data analysis followed a thematic content analysis approach (Bardin, 2011) applied to both interview transcripts and open-ended questionnaire responses. The process unfolded in three iterative stages: (i) pre-analysis, involving immersion in and familiarization with the data corpus; (ii) coding, where recurring ideas and expressions were categorized into semantic groups; and (iii) thematic synthesis, in which categories were organized into broader analytical themes. The coding process was primarily inductive, allowing themes to emerge from the data, while being guided by the study’s core foci: leadership, curriculum flexibility, pedagogical adaptation, and assessment practices.

To enhance transparency and methodological rigor, additional detail is provided regarding the analytic procedures. Coding was conducted by the primary researcher using an inductive–deductive hybrid approach, ensuring that emergent categories were grounded in the data while remaining aligned with the overarching analytical framework.

To strengthen the credibility and dependability of the analysis, a senior researcher independently reviewed a sample of the coded material and the resulting thematic structure. Any discrepancies were discussed and resolved collaboratively, contributing to the refinement of categories and increasing intersubjective agreement.

An audit trail was maintained throughout the analytic process, documenting coding decisions, category development, and interpretive memos, thereby reinforcing the traceability and coherence of the analytical procedures.

Closed-ended questionnaire items were analyzed through descriptive statistics, providing complementary quantitative insights. Both strands were compared during interpretation to identify areas of convergence (shared evidence across data types) and divergence (unique insights from one strand), following the logic of parallel integration (Creswell and Plano Clark, 2018). This integrative approach enhanced triangulation and produced a more comprehensive account of the organizational and pedagogical effects of semesterization.

The coding process generated a set of interpretive themes and subthemes which structured the analysis, as presented in Table 1. These themes capture the dimensions through which participants experienced and interpreted the implementation of semesterization.

TABLE 1

Table 1. Interpretive themes and subthemes emerging from the thematic content analysis.

4.6 Ethical considerations

Ethical integrity was central to the design and implementation of this study. Participation was entirely voluntary, and informed consent was obtained from all respondents prior to data collection. Anonymity and confidentiality were safeguarded throughout by assigning pseudonyms and applying secure procedures for data storage and handling.

In addition, the researchers adopted a participatory ethos by sharing preliminary findings with the school community in a post-research dialogue session. This feedback loop not only validated the interpretation of the data but also reinforced a collaborative research culture, acknowledging the school’s contributions and enhancing the study’s practical relevance.

4.7 Limitations

As with all qualitative case studies, the findings are context-specific and not statistically generalizable. The reliance on self-reported data introduces potential biases, such as social desirability, and the perceptions captured may reflect the institutional culture of the school at the time of data collection. In addition, the study did not include classroom observations or a systematic analysis of internal school documents, which limits the depth of insight into how semesterization was enacted in day-to-day pedagogical practice.

The sample of interview participants was intentionally narrow, focusing on the two senior leaders responsible for coordinating the reform. While this provided comprehensive access to strategic and organizational decision-making, it also constrained the range of leadership perspectives represented.

Similarly, although the teacher questionnaire reached a substantial proportion of the staff, the modest sample size and descriptive focus of the instrument limit the extent to which broader inferences can be drawn.

Nonetheless, methodological rigor was upheld through triangulation and member-checking practices (Lincoln and Guba, 1985), the use of parallel qualitative and quantitative strands, and the independent review of a subset of the coding by a senior researcher, which strengthened the dependability of the thematic content analysis. Future research could extend this design through longitudinal mixed-methods comparisons between schools using semester and trimester models, enabling stronger inferential insights and a more detailed examination of classroom-level pedagogical change.

The study’s value lies in its depth, contextual richness, and its capacity to illuminate how time reform intersects with leadership, curriculum, and science pedagogy within an autonomous school environment. Although not generalizable in a statistical sense, the findings offer analytical generalizability and transferability, providing insight into the conditions under which semester-based reforms may succeed in similar educational contexts.

The methodological approach also offers a template for international researchers examining leadership-mediated reform under conditions of local autonomy and evolving curriculum policy.

5 Results

This section presents the empirical findings of the study, organized into three interrelated strands: the implementation process, teachers’ perceptions, and the perceived advantages and challenges associated with semesterization. Each theme integrates qualitative insights and descriptive statistical data, illustrating areas of convergence and divergence across sources.

While the study is situated within a specific institutional and policy context, a public lower secondary school in Madeira, its empirical findings point to a range of issues commonly reported in school reform processes, including curriculum organization, teacher workload, and the demands of interdisciplinary collaboration. These broader implications are addressed in the section “6. Discussion,” while the present section focuses exclusively on reporting what participants described and what the questionnaire data revealed.

5.1 The implementation process

The adoption of semesterization as widely described by participants as the outcome of a deliberate, participatory process rather than a top-down imposition. Interview data indicate that early reflections on rethinking the school calendar began informally in early 2019, prompted by perceptions of the pedagogical constraints of the trimester system. These initial conversations drew on feedback from departmental meetings, informal exchanges with parents, and observations of student learning patterns, which together informed the emerging rationale for change.

These informal reflections were subsequently formalized within the school’s governance bodies, particularly the Pedagogical Council and the Educational Community Council, where semesterization was examined collectively. Participants consistently described these forums as central spaces for consultation, clarification, and gradual consensus-building. The decision to pilot the model emerged from these structured deliberations.

The leadership emphasized transparency and inclusive communication throughout the process. As one leader explained: “We did not rush the decision. We took time to study other models, to gather perspectives, and most importantly, to build trust.” Questionnaire data corroborate these accounts: 78% of teachers agreed or strongly agreed that the transition was “well-coordinated and transparent,” and 73% reported feeling “sufficiently informed and prepared” prior to implementation.

A multifaceted communication strategy supported the transition. Staff assemblies, written circulars, parent–teacher meetings, and classroom-level discussions were used to disseminate information and address concerns. A digital guidance document summarizing common questions and a support task force, including experienced teachers and mid-level leaders, helped departments adapt planning routines.

Despite overall support, some uncertainty was reported. Teachers responsible for sequential subjects such as mathematics and languages expressed concerns about pacing and potential compression of content. Leadership responded by developing shared planning templates, encouraging interdepartmental exchange, and temporarily easing administrative tasks to facilitate adaptation.

Participants also noted the role of the external policy environment. The Regional Education Department provided technical guidance and legal clarity, which teachers described as helpful in legitimizing the transition. However, teachers emphasized that the core work of aligning planning routines and adapting pedagogy occurred internally within the school.

Many teachers described the reform as building on existing pedagogical practices, particularly interdisciplinary projects and collaborative planning. As one participant stated: “We were already doing interdisciplinary projects. Semesterization just gave us the structure to do it more coherently and sustainably.” This sense of continuity contributed to stabilizing routines and reducing uncertainty during the transition.

Taken together, the findings portray the implementation process as gradually constructed, communication-rich, and supported by both internal leadership routines and external policy clarity. Quantitative and qualitative data converge in indicating that most teachers perceived the transition as organized, transparent, and aligned with the school’s ongoing pedagogical trajectory.

5.2 Teachers’ perceptions

Teachers’ perspectives on semesterization revealed a combination of positive experiences, pedagogical adjustments, and specific concerns. Survey and interview data indicate that many teachers felt actively involved in the reform process: 84% reported feeling “part of the change process,” a perception supported by qualitative accounts describing opportunities for collaborative planning and regular interaction with school leadership.

A central perceived benefit was the more balanced and coherent distribution of instructional time, with 88% of respondents indicating that semesterization enabled a steadier teaching rhythm compared to the trimester system. Teachers described calmer classroom environments, smoother sequencing of content, and extended opportunities for sustained learning tasks. Eighty percent reported perceived improvements in students’ well-being and reduced cognitive overload. Teachers also noted positive effects on their own professional experience, mentioning greater opportunities for deliberate planning, more coherent pacing, and a more manageable distribution of meetings and assessment periods. These quantitative trends are summarized in Table 2, which consolidates teachers’ responses across the main thematic domains of the questionnaire.

TABLE 2

Table 2. Summary of teachers’ responses to closed-ended questionnaire items (n = 41).

Despite these advantages, teachers also identified persistent constraints. Thirty-three percent stated that bureaucratic routines, such as reporting, internal documentation, and meeting structures, remained largely unchanged, limiting the overall impact of the reform on workload. Several teachers emphasized that administrative expectations did not adapt in parallel with the new calendar, creating occasional tensions between innovative pedagogical practices and established institutional procedures.

With regard to curriculum organization, 66% of respondents indicated that semesterization improved their ability to structure content more meaningfully and to implement interdisciplinary or project-based approaches. Teachers also reported increased opportunities for cross-departmental collaboration, with over 70% highlighting expanded planning exchanges and thematic work across subjects. However, implementation was uneven across departments: approximately 28% of teachers, especially in mathematics and languages, expressed concern that compressing annual syllabi into a single semester placed additional pressure on pacing and content coverage.

Changes in assessment practices were reported consistently. Eighty-one percent of teachers noted a more even distribution of evaluation tasks throughout the semester, and 91% perceived increased emphasis on formative assessment strategies, including learning journals, peer assessment, and reflective assignments. Teachers described the introduction of mid-semester feedback routines and a greater variety of assessment instruments aligned with extended learning cycles. At the same time, 19% raised concerns about inconsistencies in assessment criteria and pacing between subject areas or cohorts, pointing to a need for stronger internal moderation structures.

In summary, teachers generally perceived semesterization as supporting more intentional teaching practices, expanded collaboration, and improvements in student well-being. At the same time, their responses highlighted important areas requiring continued attention, including curriculum pacing in specific subjects, administrative workload, and the need for greater coherence in assessment across departments.

5.3 Advantages and challenges

The data reveal a broadly positive reception of semesterization, with 93% of teachers indicating a preference for semesterization over the previous trimester system. Qualitative accounts describe the reform as creating a more coherent rhythm of work and offering greater opportunities for intentional planning, themes echoed across interviews and questionnaire responses. A synthesized overview of the main advantages and challenges identified by teachers, integrating quantitative indicators with qualitative themes, is presented in Table 3.

TABLE 3

Table 3. Perceived advantages and challenges of semesterization (qual-quan integration).

One of the most frequently cited advantages was the increased continuity and depth of instruction. Eighty-four percent of teachers reported that longer teaching cycles enabled more thorough exploration of content and allowed for iterative learning processes. Participants also noted that organizational routines, such as meeting schedules, curriculum mapping, and assessment planning, aligned more naturally with extended instructional periods, contributing to a more coherent experience for both teachers and students.

Interdisciplinary collaboration emerged as another perceived benefit. Seventy-two percent of teachers reported increased engagement in cross-departmental planning and thematic projects. Teachers attributed this improvement to shared planning tools, structured mapping documents, and regular follow-up meetings that facilitated closer coordination across subject areas.

From an organizational standpoint, 77% of respondents indicated that semesterization improved their instructional planning. Teachers described having more time to adjust pacing, design more meaningful learning sequences, and incorporate feedback cycles more effectively. Qualitative comments highlighted that these conditions allowed for more deliberate and learner-centered approaches, reducing the pressures associated with compressed trimester schedules.

Well-being was also mentioned as a key advantage. Sixty-nine percent of teachers reported reduced stress levels, citing a more sustainable rhythm of work and fewer overlapping demands. Teachers believed these improvements extended to students, who were perceived as more emotionally balanced, calmer in class, and more engaged in learning. Several participants pointed to increased opportunities for individualized support as an additional contributor to a more positive school climate.

Despite these advantages, several challenges were identified. A recurring concern related to the significant effort required for curriculum adaptation, including redesigning planning tools, redistributing content across semesters, and coordinating new assessment sequences. Teachers noted that these adjustments required considerable time and were not accompanied by additional institutional support.

Administrative workload also persisted as an issue. Many teachers reported that procedural routines, such as mandatory meetings, reporting processes, and documentation requirements, remained unchanged, limiting the efficiency gains expected from the new model. Participants indicated that the lack of alignment between the revised calendar and administrative structures created occasional tensions in workload distribution.

Another challenge involved the risk of student fatigue in subjects taught intensively within a single semester. Teachers in these areas observed that while depth of learning increased, the concentration of content required careful pedagogical scaffolding to avoid overload or disengagement. Several respondents suggested differentiated instruction and structured formative feedback as essential strategies to mitigate these effects.

Concerns were also raised regarding equity and coherence across departments, particularly with respect to pacing decisions and assessment expectations. Teachers emphasized the need for clearer internal moderation processes to ensure consistency across subject areas and between different semesters.

Despite these challenges, the majority of participants viewed the reform positively. As one school leader remarked: “It’s not a perfect system, but it’s a better system. It gives us time to think, plan, and teach with coherence.” This sentiment was echoed across staff responses, with teachers emphasizing that the semesterization provided a structure that supported more intentional pedagogical practice and more sustainable working conditions.

6 Discussion

The findings of this study show that semesterization functioned simultaneously as an organizational adjustment and as a stimulus for pedagogical and professional change. The participatory leadership approach adopted by the school, grounded in consultation, transparency, and shared responsibility, strongly aligns with the principles of distributed leadership articulated by Spillane (2006) and the collaborative leadership orientations emphasized by Harris and Jones (2015). Teachers’ widespread perception of involvement in the reform reflects these conditions, suggesting that structural innovation was accepted largely because it was socially co-constructed rather than administratively imposed.

This dynamic also echoes Fullan’s (2007, 2021) argument that sustainable educational reform depends on “reculturing”: the development of shared norms, trust, and professional purpose that enable staff to embrace change collectively. In this study, the gradual and dialogic nature of the reform appears to have supported such reculturing, allowing teachers to integrate semesterization into their existing professional identities and collaborative routines.

At the level of pedagogy and curriculum, semesterization was perceived to enhance coherence, pacing, and depth of instruction. These findings align with international evidence demonstrating that extended learning periods reduce curricular fragmentation and promote deeper engagement (Drake and Reid, 2010; Sahlberg, 2016). Teachers’ descriptions of calmer classrooms, smoother transitions, and reduced cognitive overload reinforce the conclusion that reorganized time structures can create more favorable conditions for learning. This is consistent with Darling-Hammond et al.’s (2020) emphasis on the role of time, emotional safety, and continuity in supporting student engagement and well-being.

However, the findings also highlight discipline-specific tensions. Teachers in mathematics and languages expressed concerns about the compression of annual syllabi into single-semester units. This differentiation across subjects suggests that the benefits of extended cycles are not uniform, reinforcing Leithwood et al. (2020a,b) view that adaptive leadership must respond to the contextual variations within a school. A single structural model cannot guarantee equity unless accompanied by supportive pacing frameworks and tailored departmental planning.

Interdisciplinary collaboration was strengthened by semesterization, supported by planning templates and mapping tools. This reflects OECD (2019, 2023) recommendations underscoring the importance of flexibility and interconnected curriculum structures in fostering innovation. Teachers’ reports of increased cross-disciplinary work indicate that when time is organized coherently, it can serve as a scaffolding for collaborative professionalism, an idea central to Hargreaves and O’Connor (2018). Still, the unevenness of interdisciplinary implementation observed in this case suggests that collaboration cannot rely solely on structural enablers; it must also be intentionally cultivated through routine, expectations, and leadership follow-up.

Assessment practices were another area of notable change. Teachers’ increased emphasis on formative approaches and more evenly distributed evaluation tasks aligns closely with Black and Wiliam’s (2009) assessment-for-learning principles. Mid-semester feedback routines and a broader repertoire of assessment strategies reflect the shift from episodic, summative practices to more continuous evaluative cultures. Nonetheless, concerns regarding inconsistency across departments point to the need for stronger internal moderation processes, consistent with Robinson et al. (2009) emphasis on shared professional standards.

The challenges identified - curriculum adaptation workload, persistent administrative routines, and risks of student fatigue - share common threads with the broader literature on school reform. Ball et al.’s (2012) critique of educational performativity is particularly relevant: even when pedagogical practices evolve, entrenched bureaucratic processes can constrain the potential of innovation. In this case, unchanged administrative expectations limited some of the efficiency gains anticipated by teachers, highlighting the importance of aligning institutional structures with pedagogical goals.

Finally, the findings point to the school’s capacity for organizational learning. Leadership adjustments during the transition, such as easing administrative burdens and strengthening cross-departmental planning, reflect the forms of adaptive leadership described by Leithwood et al. (2020b), in which institutions evolve through ongoing cycles of reflection and responsive adjustment. This adaptability also reinforces Fullan’s (2021) argument that effective reform depends on iterative monitoring, meaningful feedback loops, and sustained opportunities for professional learning.

Overall, the case illustrates that semesterization can be a meaningful lever for strengthening pedagogical coherence, collaboration, and professional well-being, but only when supported by distributed leadership, adaptive planning structures, and alignment between organizational processes and instructional goals. The interplay between leadership, time, and professional agency observed here resonates with international research on the conditions that enable schools to innovate within semi-autonomous policy environments. While the findings are context-specific, they contribute to broader debates on how temporal restructuring can support more intentional, equitable, and responsive schooling.

7 Conclusion

This case study investigated how the adoption of a semester-based school calendar reshaped leadership practices, curriculum organization, and pedagogical approaches in a public lower secondary school in Madeira, Portugal. Through the lived experiences of educators and school leaders, the study revealed that reorganizing instructional time can influence school-wide practices when guided by clear pedagogical goals and supported by collaborative leadership structures. In this revised conclusion, greater emphasis is placed on the empirical scope of the findings, ensuring closer alignment with the data and avoiding interpretive excess. Within a qualitative-dominant mixed-methods design, the integration of interview evidence with teacher survey patterns allowed for the identification of shared experiences and divergences in how the reform unfolded.

The evidence suggests that semesterization, while structurally simple, created conditions for more coherent curriculum planning, strengthened opportunities for collaboration, and supported a steadier instructional rhythm. Teachers reported gains in continuity of instruction, interdisciplinary coordination, formative assessment, and professional well-being. These developments emerged through internal leadership dynamics, participatory governance, and a sense of alignment with the school’s existing pedagogical vision. However, the findings also highlight variability in implementation, notably in assessment practices and pacing in disciplines with sequential curricula, indicating that the benefits of the model were not uniform across subjects or teams.

The study further shows that structural reforms require more than calendar adjustments. Participants noted significant workload associated with curriculum redesign, persistent administrative routines that did not adapt to the new model, and concerns about maintaining coherence across departments. These tensions underscore that the pedagogical gains of time-use reforms depend on adequate systemic supports, including planning time, collaborative structures, and alignment of organizational procedures with revised temporal frameworks. Semesterization thus operates as an enabling structure whose effectiveness depends on leadership coherence and institutional capacity.

Theoretically, the study contributes to international work that frames instructional time as a strategic pedagogical and organizational resource. Consistent with Fullan’s and Leithwood’s perspectives on educational change, the findings underscore the importance of distributed leadership, collaborative professionalism (Hargreaves and O’Connor, 2018), and adaptive planning in supporting innovation. At the same time, Hall and Hord’s (2020) model of change implementation is reflected in the school’s progression through phases of adoption, adaptation, and institutionalization, suggesting that temporal restructuring becomes meaningful when supported by clear communication, shared vision, and sustained follow-up. In inquiry-rich disciplines such as science, reorganizing time can enable deeper conceptual learning and more sustained inquiry, although this depends on pacing coherence and assessment alignment.

The case of Madeira illustrates how innovation can emerge through a bottom-up, internally driven process in which leadership vision, teacher agency, and organizational learning intersect. Rather than being motivated by external pressure, the reform evolved through iterative reflection, collaborative routines, and shared ownership, demonstrating how schools can mobilize autonomy to redesign temporal structures effectively.

These insights hold wider relevance. As educational systems worldwide revisit the organization of learning time in response to post-pandemic disruption, student well-being concerns, and demands for curricular flexibility, semesterization may offer a viable framework for certain contexts, though not a universal solution. Given the single-case and self-reported nature of the evidence, transferability rather than generalizability is claimed; even so, the conditions identified - leadership trust, collaborative planning, and procedural alignment - appear relevant for systems undertaking similar reforms.

For practitioners, four key recommendations emerge:

(i)   Engage stakeholders early and meaningfully to build shared ownership and trust.

(ii)  Invest in structures that support interdisciplinary planning, curriculum mapping, and continuous reflection.

(iii) Align time structures with
pedagogical intent, ensuring coherence in assessment, curriculum sequencing, and school development planning.

(iv) Implement adaptive, feedback-informed processes, paying attention to pacing, workload, and mid-semester feedback practices for students and families.

For researchers, the study highlights several avenues for future inquiry, including comparative analyses across calendar models, longitudinal studies of leadership culture under time-use reforms, and mixed-methods research exploring disciplinary variation and subgroup differences.

In conclusion, semesterization is not simply a technical rearrangement of the school year, but a strategic reimagining of time as a lever for leadership, learning, and organizational development. When supported by a coherent vision, collaborative cultures, and ongoing monitoring, it can contribute to more intentional, integrated, and equitable educational practices. Although grounded in the Portuguese context, the experiences reported here offer insights for educational systems seeking to connect time allocation with deeper pedagogical and professional aims.

Data availability statement

The datasets presented in this article are not readily available because the data supporting the conclusions of this article consist of interview transcripts and questionnaire responses generated by the authors during the study. Due to ethical restrictions and the need to protect participant confidentiality, the raw data are not publicly available. Anonymized excerpts may be obtained from the corresponding author upon reasonable request. Requests to access the datasets should be directed to SS, c29maWEuc2lsdmFAc3RhZmYudW1hLnB0.

Ethics statement

Ethical approval was not required for this study, as it involved non-sensitive educational research with adult participants. All participants took part voluntarily, provided informed consent, and their anonymity and confidentiality were fully protected. The study was conducted in accordance with local legislation and institutional requirements.

Author contributions

SS: Conceptualization, Methodology, Writing – original draft, Writing – review & editing. NF: Conceptualization, Funding acquisition, Methodology, Supervision, Validation, Writing – review & editing. RA: Conceptualization, Formal analysis, Investigation, Software, Writing – original draft. MV: Formal analysis, Writing – review & editing.

Funding

The author(s) declared that financial support was received for this work and/or its publication. This work was carried out within the scope of the Project UID/04083/2025, “Center for Research in Education of the University of Madeira,” funded by FCT - Fundação para a Ciência e a Tecnologia: https://doi.org/10.54499/UID/04083/2025.

Conflict of interest

The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

The reviewer LN declared a shared affiliation with the authors SS and NF to the handling editor at the time of review.

Generative AI statement

The author(s) declared that generative AI was not used in the creation of this manuscript.

Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.

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