Abstract
Clearly articulated research questions shape the overall methodology and design in mixed methods research. To date, only one classification of mixed methods research questions has been proposed which includes methods-focused, content-focused, and combination mixed methods research questions. This research note proposes three additional types of mixed methods questions that explicitly address the integration procedures and relationships among the quantitative and the qualitative strands in a mixed methods study. The newly proposed questions are integration-explicating questions, relationship-elucidating questions, and three-way mixed methods questions. This paper adds to the field of mixed methods research by offering new insights into the types of questions that can be formulated to articulate the mixed methods rationale and integration intent when using this research approach.
Introduction
Research questions are the cornerstone of any study and provide researchers with a directive point of orientation for their inquiry (Bryman, 2007a). Research questions are linked to the literature review (Bryman, 2007a), are often drawn from a problem statement (Younas et al., 2024) and are pruned in such a way that they capture the essence of the phenomenon to be studied (Vandenbroucke & Pearce, 2018). Well-developed research questions provide a clear indication of what researchers intend to investigate regarding the study problem, help generate hypotheses for testing and identify hunches for further development (Newman & Covrig, 2013). Good-quality research questions inform decision-making about the design, study population, data collection, and analytical approach (Farrugia et al., 2010). Agee (2009) argued that not all good-quality research questions can produce high-quality research output, but poorly constructed and underdeveloped research questions are more likely to cause problems in the research. Poorly developed or overly broad research questions, as well as an excessive number of them, can result in the failure of a research study, which leads to a waste of time and effort (Wilkinson & Dokter, 2023). Therefore, given their importance in narrowing the problem statement and study purpose, formulating clear and focused research question(s) is a crucial step in any qualitative, quantitative, and mixed methods study (Creswell, 2008; Polit & Beck, 2020).
Mixed methods research is more complex than qualitative and quantitative research alone because it involves integrating qualitative and quantitative approaches, including collecting and analyzing qualitative and quantitative data and ensuring that both datasets are adequately integrated (Bazeley, 2018; Creswell & Plano Clark, 2018; Schoonenboom & Johnson, 2017). Fetters and Freshwater (2015) articulated the complexity of mixed methods research in their equation: 1 + 1 = 3, meaning that mixed methods research involves generating new knowledge greater than the sum of the individual quantitative and qualitative parts. Given the greater complexity of this type of research, formulating mixed methods research questions can be daunting, as it requires the researcher to be conscious of why, when, and how the quantitative and qualitative strands—including literature, methods, data, and inferences from each strand—will be integrated (Onwuegbuzie & Leech, 2006; Younas & Durante, 2023). A mixed methods study must begin with a well-formulated problem statement (Younas et al., 2024) and a clearly articulated mixed methods research question that explicitly reflects the need for and the purpose of integration (Creswell & Plano Clark, 2018; Younas, Kvist, & Stolt, 2025). Mixed methodologists recommend writing separate research questions for the qualitative, quantitative, and mixed methods study strands (Bryman, 2007b; Creswell & Plano Clark, 2018; Fetters, 2019; Onwuegbuzie & Leech, 2006; Plano Clark & Ivankova, 2016; Tashakkori et al., 2021). In regard to the mixed methods questions, Creswell and Plano Clark (2018) noted that they “highlight and specify the integration of the quantitative and qualitative data in the study” (p. 164). Additionally, mixed methods questions dictate the most appropriate mixed method design for each research project (Creswell & Plano Clark, 2018; Fetters, 2019; Tashakkori et al., 2021).
Although mixed methods questions are central to any mixed methods study, mixed methods research systematic methodological reviews (e.g., prevalence reviews) have shown that these questions are often underreported (Fàbregues et al., 2020; Granikov et al., 2020; O’Cathain et al., 2008; Younas et al., 2019). Such underreporting contrasts with the fact that many mixed methods quality appraisal tools consider the formulation of well-founded and clearly articulated mixed methods research questions as a core quality criterion (Fàbregues et al., 2019; Hong et al., 2019). Furthermore, this trend is also inconsistent with a large body of literature discussing the types of research problems addressed through mixed methods research and the nature and importance of mixed methods research questions (Creswell & Plano Clark, 2018; Fetters, 2019; Onwuegbuzie & Leech, 2006; Tashakkori & Creswell, 2007; Tashakkori et al. 2021). There has also been ample discussion in the literature on how to develop these types of research questions, including several step-by-step guides on how to formulate them (Creswell & Plano Clark, 2018; Fetters, 2019; Onwuegbuzie & Leech, 2006; Tashakkori et al., 2021). However, to date, there has been limited discussion on the variety of mixed methods questions researchers may formulate. Creswell and Plano Clark’s (2018) proposed the only known classification of mixed methods questions, distinguishing between three types, namely, methods-focused, content-focused, and combination research questions.
Creswell and Plano Clark’s (2018) classification of mixed methods research questions is a useful resource for researchers to delineate the method, content, and design of mixed methods studies. Nevertheless, with the advancement of the field, reflected in a more explicit articulation of the complex purposes addressed via mixed methods and a more frequent use of integration procedures at various levels of a mixed methods study, the advancement and refinement of this classification may result in added benefits for mixed methods researchers. We argue that Creswell and Plano Clark’s (2018) classification has two shortfalls. First, the three types of research questions they propose are rather broad, and while they focus on clearly articulating the overall mixed methods research design and/or content to be covered in a specific MMR study, their breadth may inadvertently undermine the necessity of articulating the unique integration procedures and purposes of mixed methods studies. For example, in quantitative and qualitative methodologies, research questions for various research designs are distinct. If a researcher is interested in conducting a randomized control trial, the research question should explicitly state the intention of testing and/or determining the effectiveness of an intervention. In line with this argument, the second shortfall is that these broad mixed methods questions, while useful for initial design specification, are inadequate to capture the nuanced details of a wide range of mixed methods designs, specifically the procedures and purposes used across these designs.
Purpose
The purpose of this Research Note is to advance and refine Creswell and Plano Clark’s (2018) classification of mixed methods research questions, thereby addressing the shortfall that the current broad categories fail to capture the necessary procedural and integrative nuance of mixed methods designs. This refinement is achieved by offering three additional types of questions that can help researchers more precisely explain the integration procedures used in mixed methods research and clearly illustrate the relationships between quantitative and qualitative constructs examined in a mixed methods study.
Creswell and Plano Clark’s Classification of Mixed Methods Research Questions
Creswell and Plano Clark’s (2018) proposed three types of mixed methods research questions. First, methods-focused questions are formulated to demonstrate the integration of quantitative and qualitative methods within each type of mixed methods design used. For example, in the context of a convergent design, a methods-focused question could be: To what extent do qualitative results align with the quantitative results? Second, content-focused questions highlight the mixing of quantitative and qualitative results through clear articulation of the content of the study while implicitly addressing the research methods and integration intent. For example, how do lived experiences of women in caregiving support or refute the results of their resilience changes during the caregiving process? Finally, combination mixed methods questions are formulated in such a way that both the design and content of the study are explicit. For example, what results emerge from comparing the exploratory qualitative results on women’s caregiving experiences and resilience with quantitative results on the levels and factors affecting resilience measured using the caregiver resilience scale?
Methods
This Research Note is based on our experiences of designing, conducting and teaching mixed methods research at graduate-level courses and training workshops in Spain, Finland, Pakistan, Canada, USA, and Italy. Both researchers have conducted mixed methods research systematic methodological reviews in multiple fields and disciplines, designed and conducted large scale and complex mixed methods studies, and published methodological papers on research problems in mixed methods, designs, integration, and quality. Rather than conducting a formal literature review, we used our knowledge of the mixed methods literature and our experiences of writing, teaching, and publishing mixed methods studies.
Advancing the Classification of Mixed Methods Research Questions
Types of Mixed Methods Questions and Examples
Integration-Explicating Mixed Methods Questions
Integration is the core and distinguishing feature of mixed methods research (Bazeley, 2018; Fetters, 2019; Creswell & Plano Clark, 2018; Tashakkori et al., 2021). A well-designed and rigorous mixed methods study involves clear and synergistic integration of quantitative and qualitative strands. Therefore, it is essential that mixed methods research questions be formulated in such a way that researchers can make explicit the integration intent and procedures, thereby implicitly highlighting the added value over a monomethod design. Developing mixed methods research questions in this way can prompt researchers to ensure integration is adequately achieved at multiple stages of the study—including the objective, research design, sampling, data collection, data analysis, and interpretation dimensions, in accordance with Fetters and Molina-Azorin’s (2017) integration trilogy classification—as required by the research question and the type of design employed. We define the integration-explicating mixed methods questions as those that explicate the type of integration intent and procedures used in a mixed methods study. These questions may appear to be similar to the methods-focused mixed methods questions outlined by Creswell and Plano Clark (2018). However, they are distinct in being more specific, allowing researchers to better determine the particular integration procedures used rather than merely dictating its overall design. Creswell and Plano Clark (2018) methods-focused questions are limited in that they only allow researchers to articulate the convergent and sequential nature of the mixed methods design. However, it is well known that a mixed methods study can include more than one integration procedure, a feature not captured by mixed methods-focused questions (Fetters, 2019; Younas & Durante, 2023a; Tashakkori et al., 2021). In response to this limitation, integration-explicating mixed methods questions allow articulation of multiple integration procedures to be used in a study. For example, a researcher may frame an integration-explicating mixed methods question as follows: How can qualitative results about individuals’ experiences of living in poverty inform the understanding of poverty stigma (exploration integration procedure) and the development of a data collection instrument to measure poverty stigma among individuals of low socioeconomic status (building integration procedure)?
Several types of integration procedures in mixed methods research have been proposed in the literature, including building, connecting, merging, embedding, linking, constructing a case, corroborating, and so forth (Fetters, 2019; Fetters et al., 2013; Younas & Durante, 2023a). Integration-explicating mixed methods research questions can be useful in clarifying the intent and potential integration method to be employed in a mixed methods study. For example, suppose a researcher conducts a mixed methods grounded theory of organizational readiness to change. In that case, a qualitative research question may include Under what conditions does organizational readiness to change occur? And a quantitative question may include What organizational factors predict organizational readiness to change? Finally, an integration-explicating mixed methods research question could illustrate how the qualitative results from the first phase may be used to generate hypotheses for testing in the subsequent quantitative phase. The relevant integration procedure is “generating a hypothesis” (Fetters, 2019; Younas & Durante, 2023). In this case, an integration-explicating mixed methods question can be framed as follows: How does qualitative data about organizational readiness to change inform the generation of hypotheses for testing concerning predictors of organizational readiness to change?
Relationship-Elucidating Mixed Methods Question
Mixed methods research is highly relevant for exploring, examining, and comprehensively understanding the emerging patterns, linkages, and relationships between the qualitative and quantitative data and results (Creswell & Plano Clark, 2018; Schoonenboom & Johnson, 2017). The examination of relationships between both strands is particularly evident in the analysis and interpretation stages of the mixed methods study, in which the researcher brings together the results and inferences from each strand and examines their “fit”—that is, if the relationship between the two types of results is one of complementarity, expansion, convergence, or divergence. Whether one or the other type of relationship is more prevalent at this stage depends on the nature of the relationship between the quantitative and the qualitative constructs, as represented by the mixed methods research question and the design implemented. Therefore, research questions in mixed methods play a central role in guiding researchers to design and implement the quantitative and qualitative strands in a way that the relationships of interest between the two strands—relationships that arise from the rationale for using mixed methods—can be thoroughly and adequately examined when both types of data are integrated at the end of the study.
Relationship-elucidating mixed methods questions can be instrumental in clarifying the nature and types of relationships being studied in a mixed methods study. We define these questions as those that explicate the relationships to be examined between the qualitative and quantitative strands, illustrating how one type of result (i.e., qualitative or quantitative) may relate to the other. We argue that these questions are distinct from combination mixed methods questions (Creswell and Plano Clark, 2018) in that relationship-elucidating mixed methods questions are focused on the tentative relationships and associations between quantitative and qualitative constructs, while combination mixed methods questions explicate the nature of the mixed methods design and its outcomes. For example, in the previously mentioned study on organizational readiness to change, an example of a relationship-elucidating question might be: How does leaders’ motivation (quantitative strand) impact the change process in an organization (qualitative strand)? As shown, this question illustrates the hypothesized relationship between leaders’ motivation and change processes within an organization, highlighting the rationale for a mixed methods study without explicating the mixed methods design to be used. For instance, this question could be addressed using a convergent mixed methods design, collecting both qualitative and quantitative data on leaders’ motivation and their views on change processes, or using a mixed methods grounded theory design to generate a theory of organizational change from leaders’ perspectives.
Three-Way Mixed Methods Research Questions
The complexity of mixed methods research requires researchers to formulate research questions that capture the nuances of the phenomena to be studied and provide an indication about the critical aspects of the study (Creswell & Plano Clark, 2018; Younas et al. 2024). Mixed methods questions that offer precise information about the methods, content, and integration procedures to be used can effectively guide the design and conduct of a study. Integration-explicating and relationship-elucidating mixed methods questions specifically illustrate different stages of the design and analyses in a mixed methods study. However, three-way mixed methods questions are more comprehensive, as they outline the overall intent of a mixed methods study.
We define three-way mixed methods questions as those comprising three parts that explicate the method, integration procedure, and content of the mixed methods study. They differ from combination mixed methods questions (Creswell & Plano Clark, 2018) in that they exemplify the type of integration procedure that can be used. In the previously reported example, a three-way mixed methods question might be: How can individuals’ experiences of organizational readiness (Part 1) be used to develop hypotheses about potential predictors of readiness (Part 2, Integration procedure) and then examine the extent to which quantitative results about these predictors are consistent with or divergent from qualitative experiences of organizational readiness (Part 3)?
Discussion
The purpose of this Research Note is to refine and expand Creswell and Plano Clark’s (2018) classification of mixed methods research questions. A more precise characterization and formulation of mixed methods research questions is critical to inform the nature and type of mixed methods design, the methods used in the qualitative and quantitative strands, and the most relevant procedures for integration in a particular study (Younas et al., 2019). If researchers fail to characterize their mixed methods questions, it may lead to confusion in selecting the most pertinent design, analytical procedures for the qualitative and quantitative phases, and integration procedures. For example, if a researcher is interested in examining how one or more variables or constructs influence each other, framing a relationship-elucidating mixed methods question may hint at the need for a convergent mixed methods design. This would include correlation or regression analyses in the quantitative phase, some form of inductive analysis in the qualitative phase, and the application of the linking, merging or comparing integration procedures (Younas & Durante, 2023a) to examine how both constructs are related to each other. In such cases, combination or integration-explicating mixed methods questions may be insufficient. Nevertheless, a three-way question can be useful, but it may be complex to develop, particularly if the researcher is interested in two or more qualitative and quantitative constructs.
We proposed three new mixed methods questions, namely, integration-explicating, relationship-elucidating, and three-way questions. Alvesson and Sandberg (2013) noted that one of the most essential criteria of an excellent research question is that it is researchable, meaning it is framed in such a manner that scientific empirical testing is possible. The three new types of questions introduced in this note may meet this criterion, as they are grounded on the core features of mixed methods research and allow researchers to explicitly state the method, integration strategies, linkages, and relationships among the studied phenomena. Nevertheless, it is also essential that the problem statements and research purposes from which mixed methods questions are derived are well-articulated, so that researchers can ensure that the qualitative and quantitative parts of their mixed methods questions are coherent and logical (Younas & Durante, 2023b. Choosing integration procedures in mixed methods research can be difficult for many researchers because of the array of integration procedures suggested in the literature (Fetters, 2019; Younas & Durante, 2023; Younas et al., 2025). Therefore, it is important that these procedures are selected at the study’s conceptualization and design stages rather than after data collection has begun (Fetters, 2019). Integration-elucidating mixed methods research questions can be beneficial for researchers to select the most pertinent integration procedures for use in their mixed methods studies during the design and conceptualization stages. Nevertheless, it is also noteworthy that integration in mixed methods research has been conceptualized distinctly across disciplines. For example, many integration procedures such as merging, linking, comparing, enhancing, and explaining can have overlapping meanings (Fetters, 2019; Younas & Durante, 2023a). For example, Fetters (2019) described connecting as selecting a sample for the qualitative phase based on the quantitative phase. On the other hand, Pluye et al. (2018) described connection as linking qualitative and quantitative phases and data by connecting the results of quantitative phase with the subsequent qualitative phase or vice versa. In the similar vein, merging integration procedure means bringing qualitative and quantitative data together for analysis (Fetters et al., 2013) and comparing also means compare the results of qualitative and quantitative phases (Pluye et al., 2018). The challenge is that these terms often have overlapping functions. For example, a researcher who “merges” data for developing a joint display inevitably “compares” the results to draw meta-inferences and is essentially “connecting” the two databases. This functional overlap among key integration procedures highlights a lack of conceptual standardization. Consequently, operationalizing these integration procedures distinctly within each mixed methods design and precisely articulating them in a research question before the data are available can be highly challenging for researchers. Furthermore, integration procedures and their operationalization may change during the conduct of a mixed methods study, depending on the nature, type, and quality of the data collected, as well as the need to revisit analytical methods. This adds to the challenge of developing a well-articulated integration-elucidating mixed methods question.
Clearly articulating relationships and discerning the relational connections among variables or constructs directly affects the choice of statistical, qualitative, and mixed methods analysis (Polit & Beck, 2020). Therefore, mixed methods researchers should be attentive to make explicit the relationships among the constructs examined in each strand to ensure that adequate methods of analysis are chosen. Relationship-elucidating mixed methods research questions may offer researchers an opportunity to make the linkages explicit at the conceptualization and design stages, thereby helping to avoid any erroneous analytical choices and decisions. We argue that three-way questions are comprehensive and encompass three key features of mixed methods research studies: the method, the integration procedure, and the content of the study. Hence, these questions may promote more integrative thinking, allowing researchers to identify the links among variables or constructs, chosen methods, and integration procedures at an early stage of the study and refine them as desired and needed to minimize flaws in the mixed methodology. Failure to clearly articulate mixed methods questions can lead to erroneous design for individual strands and the overall mixed methods component, inappropriate analysis methods for the individual strands and the integration, and underdeveloped inferences and meta-inferences in the study (Fàbregues et al., 2024; Fetters, 2019; Younas, Fàbregues, & Creswell, 2023).
Operationalization of Types of Mixed Methods Research Questions in the Expanded Classification
Note. QUAN = Quantitative, QUAL = Qualitative.
Contribution to the Field of Mixed Methods
This paper contributes to the field of mixed methods by introducing three new types of mixed methods research questions in an attempt to make explicit the integration procedures, linkages between qualitative and quantitative strands, and the intended variables or constructs to be studied. These new types have the potential to expand Creswell and Plano Clark’s (2018) classification, offering a new way of thinking about research questions within this methodological approach. This paper offers new insights into the types of mixed methods research questions that can be formulated to explicate the methodology and design, and to exemplify the types of integrative and analytical approaches that can be used. While we recognize that the mixed methods research questions presented here are not the only additional possible types that can advance the abovementioned classification—given the complex nature and variety of possibilities in designing and conducting mixed methods studies—these additional types may prompt active discussion and engagement within the mixed methods community about the nature of research questions and their need for and importance of contributing to rigorous study designs.
Conclusions
Mixed methods research questions should be well formulated to offer a clear indication of the research design, study methods, population to be studied, and integration procedures to be used. Carefully crafted research questions are a prerequisite for designing and conducting rigorous mixed methods research. Without clear mixed methods research questions, researchers may run into the problem of conducting poor-quality studies that provide no new insights into the phenomena under study. The expanded classification of mixed methods research questions may be useful to novice and expert researchers in clearly articulating the questions for their mixed methods studies. However, it is also important to note that these additional types of questions were not developed on the basis of a systematic methodological review of literature.
Footnotes
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of Conflicting Interests
The authors declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: This article was submitted to the journal before Sergi Fàbregues started his role as co-editor in chief, and he was entirely removed from the peer review and acceptance process. Sergi Fàbregues is the co-editor in chief, and Ahtisham Younas is an associate editor for Journal of Mixed Methods Research.