Avoiding Fragmentation and Salami Slicing in Mixed Methods Research

Abstract

Mixed methods research (MMR) offers rich opportunities for doctoral inquiry, but its complexity demands careful navigation of design, data integration, and dissemination. For doctoral candidates, one under-recognised risk is the ethical and methodological challenge of fragmentation and salami-slicing practices that undermine the coherence and transparency central to MMR. Fragmentation involves separating components of a study across publications, while salami slicing divides a dataset into minimally contributive outputs, often misaligning with the original study design. This discussion paper addresses the implications of these practices in the context of doctoral research and supervision. It highlights the need for supervisory guidance in ethically planning publications, particularly in aligning dissemination with MMR design logic. Drawing on doctoral inquiry and supervisory discourse, the paper proposes design-informed strategies to help candidates and supervisors protect the integrity of MMR. In doing so, it contributes to the methodological literature by offering actionable guidance for ethically navigating dissemination within the context of complex, mixed methods doctoral projects.

Introduction

Mixed methods research (MMR) is increasingly adopted by doctoral candidates seeking to investigate complex, multifaceted research questions. However, MMR is a highly integrative and philosophically diverse design that presents unique challenges. Doctoral researchers navigating MMR must manage the demands of collecting and integrating both qualitative and quantitative data, aligning their methods with philosophical underpinnings, and planning publications. These pressures unfold within a broader academic environment, making the supervisory relationship a critical support structure for guiding students through these complex expectations.

Although the terms are sometimes used interchangeably, MMR and multimethod research reflect distinct methodological approaches. Multimethod research most often refers to the use of multiple methods within a single paradigm, either qualitative or quantitative, to deepen understanding or strengthen triangulation, without combining data across paradigms (Anguera et al., 2018; Sarker et al., 2025). For instance, a qualitative study might employ both focus groups and interviews to capture varied perspectives within an interpretive framework. Although some scholars argue that multiple methods may also be a mix of qualitative and quantitative paradigms, they are separate in nature, and the intention is to allow these studies to be implemented within their traditional philosophical paradigm (Hesse-Biber & Johnson, 2015; Salmons, 2025). In contrast, MMR involves the intentional integration of qualitative and quantitative data to address research questions. This integration may occur during the study’s design, analysis, or interpretation, and is typically guided by a pragmatic philosophical stance (Creswell & Plano Clark, 2018). In this way, the markers of MMR relate to the philosophical stance and the integration of data/transformation of data to answer the research questions (Hesse-Biber & Johnson, 2015; Salmons, 2025). The recommendations in this discussion specifically relate to mixed methods designs, where integration is central. However, the insights offered may also be applicable to researchers conducting multimethod studies, particularly in the planning and dissemination phases.

One challenge in MMR is the underexplored risk of fragmentation and salami slicing, which can unintentionally arise during data dissemination. Fragmentation involves reporting components of a study separately, resulting in disjointed findings that fail to convey the study’s full scope and interconnectedness as a research methodology (Joob & Wiwanitkit, 2017). Salami slicing refers to dividing substantial research into smaller, less meaningful publications, often to inflate a researcher’s publication record (Werner, 2021; Xie & Ali, 2023). These practices disrupt MMR’s methodological underpinning of integrating diverse datasets and compromise its transparency, reproducibility, and overall impact.

Given the complexity and often expansive nature of MMR designs, multiple publications from a single study may be justified to address distinct research questions effectively; however, careful planning is crucial to ensure these outputs maintain coherence and reflect the study’s overarching purpose. This paper emerged from a doctoral research project and related supervisory discourse examining how best to uphold the integrity of MMR through ethically guided dissemination strategies. This discussion proposes design-specific publication strategies to support doctoral candidates and supervisors in navigating publication planning in MMR. It presents a conceptual and practical overview of fragmentation and salami slicing, explores the implications for research integrity, and offers structured recommendations aligned with common MMR designs.

Principles of MMR and Design

MMR is grounded in the integration of both quantitative and qualitative data to provide a more comprehensive and holistic understanding of complex research questions (Creswell & Plano Clark, 2018). Integrating these two types of data enriches the research process by offering multiple perspectives, enhancing the validity and depth of the findings, and addressing the limitations of relying on a single method (Creswell & Plano Clark, 2018).

In its purest form, MMR triangulates, integrates, and/or merges both quantitative and qualitative data, offering a rich interplay of diverse perspectives. Triangulation plays a crucial role by cross-verifying data from multiple sources, thus increasing the credibility and validity of the results (Tashakkori et al., 2020). This approach reduces the risk of bias and strengthens confidence in the results by comparing findings from qualitative and quantitative methods (Kaushik & Walsh, 2019; Plano Clark & Ivankova, 2016).

While the pragmatic paradigm is commonly associated with MMR, it is not the only philosophical foundation used. Other philosophical approaches, such as transformative and critical realism, have also been used to guide MMR (Hesse-Biber & Johnson, 2015). The transformative paradigm emphasises social justice and positions research as a tool for empowering marginalised groups and addressing inequities (Mertens, 2023). Critical realism focuses on uncovering both observable patterns and the underlying mechanisms or structures that shape them, making it well-suited to the layered nature of MMR (Zachariadis et al., 2013). Pragmatism emphasises the practical utility of blending research methods to address real-world problems (Kaushik & Walsh, 2019; Plano Clark & Ivankova, 2016). Pragmatism allows researchers to use the most suitable techniques from both qualitative and quantitative dichotomies, ensuring that the research approach is aligned with the study’s specific needs.

MMR encompasses various design frameworks, each with unique approaches to data collection, integration, and interpretation. Common MMR designs include convergent parallel design where quantitative and qualitative data are collected simultaneously and then merged to provide complementary insights; sequential designs, which involve distinct phases where findings from one method inform the next; embedded designs, where one type of data supports a primary method; and transformative or multiphase designs, which often span multiple studies with iterative cycles to address complex research questions (Figure 1; Creswell & Plano Clark, 2011, 2018). The choice of design informs when, how, and to what extent data is integrated and triangulated, influencing the coherence and focus of the study’s findings (Fetters et al., 2013). Consequently, the design framework should impact the structure of publications arising from the research, as each design may yield distinct yet interrelated insights that warrant separate reporting to convey the full depth of the study.

Figure 1.

Various MMR designs with planned publications to avoid salami slicing and fragmentation.

What is Fragmentation and Salami Slicing?

Fragmentation and salami slicing, though often used synonymously despite their differing meanings, conflict with MMR’s philosophical underpinning (Kaushik & Walsh, 2019; Plano Clark & Ivankova, 2016). Fragmentation undermines the complementary nature of MMR by separating individual components, such as the qualitative and quantitative findings, without meaningful integration. This results in disjointed publications that lack the synergy intended in MMR, reducing the potential for a comprehensive understanding of the research question (Joob & Wiwanitkit, 2017). Comparatively, salami slicing refers to the splitting that occurs in a single study or dataset across multiple manuscripts for publication. This dilutes the overall impact of the research and can obscure the broader context of the study (Werner, 2021; Xie & Ali, 2023). Both the practice of fragmentation and salami slicing lead to incomplete and superficial insights in answering a research question, hindering the comprehensive understanding of complex problems that MMR aims to achieve. These practices also compromise transparency and reproducibility, which are essential elements of rigorous research (Bakken, 2019; Reischer & Cowan, 2020).

Importance of Reporting in MMR

Effective reporting in MMR is crucial for capturing the comprehensive insights derived from integrating quantitative and qualitative data. For doctoral candidates and emerging researchers, transparent and coherent reporting serves not only as a demonstration of methodological rigour but also as an essential academic practice that enables scholarly dialogue, replication, and future research (Albright et al., 2013; Reio & Werner, 2017). One measure of a quality dissemination approach is that researchers enable others to understand, replicate, and build upon their work by providing a clear and detailed explanation of methodologies and findings.

From an organisational perspective, robust reporting in MMR provides valuable evidence that can inform policy and practice (Albright et al., 2013). Organisations rely on high-quality evidence to develop effective programmes, improve service delivery, and address complex issues. MMR offers a nuanced and detailed understanding of research problems, making the findings more applicable and actionable. Transparent reporting ensures all organisational stakeholders can access and use the research outcomes, fostering informed decision-making and strategic planning (Albright et al., 2013).

Well-reported MMR also has implications for broader societal engagement. Clear and accessible reporting builds public trust and demonstrates a commitment to ethical standards and accountability. When research findings are effectively communicated, the community can better understand and appreciate the study’s contributions, enhancing public engagement, implementation of research findings, and support for research initiatives (Kara, 2018). Additionally, comprehensive dissemination of findings can lead to societal benefits such as improved health practices, educational advancements, and social innovations (Albright et al., 2013).

Ethical Considerations, Transparency, and Reproducibility

Fragmentation and salami slicing in MMR raise significant ethical concerns, particularly regarding the researcher’s responsibility to conduct and report their work with integrity (Werner, 2021; Xie & Ali, 2023). Researchers are entrusted with a duty to present findings transparently and honestly, ensuring that their work contributes meaningfully to the scientific community and society (Albright et al., 2013; Joob & Wiwanitkit, 2017). Both practices diminish the perceived reliability and significance of the findings, as the research intended to inform policy or practice may lose impact and credibility.

Transparency is essential in MMR to ensure that methodologies, data collection, and analysis are accessible and comprehensible to the broader research community (Hesse-Biber & Johnson, 2015). Fragmented reporting and salami slicing can obscure the study’s design, objectives, and integrated findings, limiting the opportunity for meaningful discussion and hindering the study’s overall contribution to scientific knowledge. Reproducibility, likewise, is critical to verifying findings and confirming the reliability of conclusions drawn from complex, integrative studies (Creswell & Plano Clark, 2018). For doctoral candidates, these concerns are particularly prominent, as the integrity of reporting reflects both on the researcher’s emerging scholarly identity and the guidance provided through supervision. Salami slicing compounds this issue by providing incomplete details in each publication, which makes it difficult to reconstruct the original study design or replicate findings accurately.

MMR Design Considerations and Implications for Publications

The design of a mixed methods study plays a pivotal role in determining the appropriate publication strategy. Certain designs, especially those that employ multiphase or complex frameworks, may justify multiple publications as they often address separate, complementary research questions within an overarching study. In contrast, simpler MMR designs, where data sets are integrated to answer a single, cohesive research question, typically require consolidated reporting to maintain the integrity of the findings and the study’s intent.

To avoid fragmentation or salami slicing, it is essential to plan publications based on the chosen MMR design at the beginning of the study. This is particularly important in doctoral research, where early planning can prevent misalignment between dissemination outputs and the study’s methodological rationale. For example, a convergent parallel design typically involves the simultaneous collection of quantitative and qualitative data sets, which are then integrated to answer a single research question (Figure 1; Creswell & Plano Clark, 2011, 2018). In this case, publishing separate results for each data set without integration would be counterproductive, as the intent of the design is to combine findings to achieve a fuller understanding. Thus, a single, integrated publication would generally be more appropriate and ethically sound for convergent designs.

Conversely, sequential designs (e.g. exploratory or explanatory) may involve distinct phases that address different but interrelated research questions. For instance, an exploratory sequential design may begin with qualitative data collection and analysis, followed by quantitative methods to provide context to or explain the initial findings (Figure 1; Creswell & Plano Clark, 2011, 2018). Each phase answers separate aspects of the study’s overarching question and, therefore, warrants individual publications that reflect the unique contributions of each phase. Similarly, multiple publications are often necessary and appropriate for complex designs, such as multiphase or transformative designs. These designs are typically used for extensive studies addressing broad, complex issues through multiple questions and phases (Creswell & Plano Clark, 2011, 2018). Each phase may be designed to generate insights into different facets of a complex phenomenon, often necessitating separate publications to capture the breadth of the findings adequately (Figure 1).

However, in both sequential and complex multiphase designs, it is essential that each publication reflects the specific research questions and goals established for its respective phase. For doctoral candidates, articulating how each output connects to the overall design enhances transparency and demonstrates methodological maturity. Careful planning is needed to ensure that all publications contribute meaningfully to the overarching research narrative and provide a cohesive view of the study’s comprehensive findings.

Recommendations for MMR Publications

We suggest the following recommendations for doctoral candidates and supervisors to consider when publishing MMR. Adhering to best practices and established reporting guidelines is essential to ensure the integrity and impact of MMR.

1. Doctoral researchers should plan publications strategically to reflect the MMR design. Developing a publication strategy early in the study ensures alignment with the chosen MMR design, but it should also consider milestone requirements, candidate needs, and the preferences of the supervision team. Additionally, when multiple publications arise from an MMR study, it is important to acknowledge the broader research and data that are reported elsewhere.

2. Candidates and supervisors should clearly indicate where integration of the data occurs, along with rationales. Demonstrating how the different data types complement each other contributes to a comprehensive understanding of the research problem. Integration should be evident in the study design, data collection, and presentation of findings (Creswell & Plano Clark, 2011, 2018). This aligns with the fundamental principles of MMR and enhances the utility and coherence of the research outputs.

3. Maintain transparency in reporting by including detailed descriptions of the study’s methodology, the rationale for choosing specific methods, data collection procedures, and data analysis strategies (Tashakkori et al., 2020). Clear and thorough reporting allows other researchers to replicate the study and evaluate its rigour and validity. Transparency in reporting also involves discussing the study’s limitations and the potential impact these limitations may have on the findings and their interpretation (Ngulube & Ukwoma, 2021; O’Cathain et al., 2008).

4. Established tools like Good Reporting of a Mixed Methods Study (GRAMMS) and the Mixed Methods Appraisal Tool (MMAT) should be used appropriately to guide reporting and preparation. The GRAMMS checklist should be used to prepare and structure manuscripts for publication, ensuring clear and transparent reporting of MMR findings (O’Cathain et al., 2008). Additionally, the MMAT is used mainly in literature reviews to critique the quality of mixed methods studies (Hong et al., 2019). However, MMAT can also serve as a useful preparatory tool for researchers, helping them critically evaluate their methodology and address potential limitations before submission. Leveraging these tools effectively ensures adherence to best practices and supports robust reporting.

5. Researchers should also consult editorials from key mixed methods journals, such as those by Fetters and colleagues (Fetters & Freshwater, 2015; Fetters & Molina-Azorin, 2019), which outline expectations for methodological clarity, integration, and contribution in MMR publications. These editorials provide valuable guidance for structuring high-quality mixed methods manuscripts, with particular relevance to doctoral research training and supervision.

6. Journal-specific reporting guidelines should be adhered to. Different journals may have specific requirements for MMR manuscripts, including the structure, level of methodological detail, and presentation of integrated findings. Reviewing and complying with these guidelines increases the likelihood of acceptance and ensures the research is effectively communicated to the intended audience (EQUATOR Network, n.d.).

7. To effectively present MMR, avoid jargon and ensure your writing is clear and accessible. Overcomplicating manuscripts can cause confusion and misinterpretation, reducing the research’s impact. Focus on delivering clear, concise information that is easy to follow while providing sufficient detail for the readers.

By adhering to these best practices, following established guidelines, and ensuring compliance with journal-specific requirements, doctoral candidates can strengthen the methodological coherence and ethical integrity of their research outputs, ensuring their MMR is robust, transparent, and valuable to a wide range of stakeholders, including academics, practitioners, and the public.

Conclusion

Maintaining the integrity and coherence of a mixed method study is crucial for advancing knowledge and ensuring that the findings are valuable and applicable to the scientific community, organisations, and society at large. Fragmentation and salami slicing are detrimental practices that compromise the holistic understanding, transparency, and reproducibility of the research, which are risks that are particularly relevant in the context of doctoral education. For doctoral candidates, thoughtful dissemination planning represents both a scholarly and ethical responsibility, shaped through supervisory dialogue and methodological training. By adhering to established guidelines, aligning publication strategies with mixed methods design logic, and committing to ethical reporting practices, doctoral researchers can ensure their work contributes meaningfully to the field. Upholding these standards not only enhances the credibility of the research but also models academic integrity and fosters trust within the supervisory relationship, the academy, and the wider community.