Background
Authors | Synthesis designsa
|
---|---|
Frantzen and Fetters [40] | 1. Convergent meta-integration: quantitative, qualitative, and mixed methods studies are synthesized without data transformation. 2. Convergent qualitative meta-integration: quantitative data are transformed into qualitative format. 3. Convergent quantitative meta-integration: qualitative data are transformed into quantitative format. Each design can be of basic type (when a review includes quantitative and qualitative studies) or advanced type (when a review includes qualitative, quantitative, and mixed methods studies). |
Heyvaert et al. [22] | An 18-design framework based on the emphasis of approaches (equal or dominant status of qualitative or quantitative approach), the temporal orientation (sequential or convergent), and the level of integration (partial or full integration). |
Pluye and Hong [10] | 1. Sequential exploratory: results of the qualitative synthesis inform the quantitative synthesis. 2. Sequential explanatory: results of the quantitative synthesis inform the qualitative synthesis. 3. Convergent: results of qualitative and quantitative studies are integrated using data transformation techniques. |
Sandelowski et al. [8] | 1. Segregated: qualitative and quantitative findings are treated separately. 2. Integrated: qualitative findings are transformed into quantitative data (quantitizing) or quantitative finding are transformed into qualitative data (qualitizing). 3. Contingent: cycle of research synthesis studies conducted to answer questions raised by previous synthesis. |
Methods
Level of research | |||
---|---|---|---|
Primary | Secondarya
| Tertiary | |
Research | Systematic review: collation and interpretation of existing empirical studies using systematic and explicit methods [48]. | Review of reviews: collation and interpretation of existing systematic reviews [48]. | |
Types of research | Qualitative review: review combining qualitative studies. | Review of qualitative reviews: review combining qualitative reviews. | |
Quantitative study: research that aims at testing theories by examining the relationship among variables [49]. | Quantitative review: review combining quantitative studies. | Review of quantitative reviews: review combining quantitative reviews. | |
Mixed methods study: research involving collecting and integrating both quantitative and qualitative data [49]. | Mixed studies review: review combining qualitative, quantitative, and/or mixed methods studies. | Review of mixed studies reviews: review combining mixed studies reviews. | |
Data | Primary data collected from fieldwork or lab work. | Findings from included studies. | Findings from included reviews. |
Data analysis | Synthesis: a step within a systematic review consisting of creating something new of findings from included studies [48]. | Synthesis of findings across included reviews. |
Information sources and search strategy
Concepts | Terms searched |
---|---|
Mixing studies, methods, or data | 1. mixed method*.mp 2. mixed stud*.mp 3. mixed research.mp 4. mixed knowledge.mp 5. multi-method*.mp 6. multimethod* 7. multiple method*.mp 8. OR/1-7 |
Quantitative and qualitative | 9. quantitative.mp 10. trial*.mp 11. qualitative.mp 12. 9 or 10 13. 11 and 12 |
Reviews or syntheses | 14. systemat* review*.mp 15. systemat* synthes*.mp 16. critical review*.mp 17. critical synthes*.mp 18. structured review*.mp 19. structured synthes*.mp 20. integrat* review*.mp 21. integrat* synthes*.mp 22. (literature adj3 review*).mp 23. (literature adj3 synthes*).mp 24. research review*.mp 25. research synthes*.mp 26. evidence review*.mp 27. evidence synthes*.mp 28. comprehensive review*.mp 29. comprehensive synthes*.mp 30. OR/14-29 |
Specific synthesis methods | 31. realist review*.mp 32. realist synthes*.mp 33. meta-narrative review*.mp 34. meta-narrative synthes*.mp 35. critical interpretive review*.mp 36. critical interpretive synthes*.mp 37. 31 or 32 or 33 or 34 or 35 or 36 |
Combination and limits | 38. 8 or 13 39. 30 and 38 40. 37 or 39 41. limit 40 to (English or French) |
Eligibility criteria and selection
Data collection and synthesis
Synthesis method | Aim | Description |
---|---|---|
Bayesian synthesis [53] | To measure the likelihood of different values for parameters of interest. | Incorporates prior distributions of unknown parameter values that are then updated by deriving posterior probability distributions generated through statistical analysis of the estimates. |
To identify and statistically test patterns across individual case studies. | Converts qualitative cases into quantitative variables by extracting data using a same set of closed-ended questions. The answers to these questions are then aggregated to establish frequency of occurrence (that can be further statistically analyzed, as appropriate). | |
Configurational comparative method [56] | To build or test theories and assumptions by identifying configurations of causal conditions, i.e., combination of conditions (independent variables) that are necessary and/or sufficient for a given outcome (dependent variable). | Consists in a comparative case-oriented research approach that uses Boolean algebra to generate configurations between conditions and outcomes across cases. |
Cross-design synthesis [57] | To combine results from quantitative studies with complementary designs (e.g., RCT and observational studies). | Involves an in-depth assessment of key biases of each study, an adjustment of each study’s results based on the identified biases and the development of a model for combining the results within and across designs. |
Meta-analysis [58] | To obtain a single summarized “effect size.” | Uses statistical methods for combining results of studies into a weighted average of point estimates. |
Meta-regression [59] | To relate the size of effect to one or more characteristics of the included studies (to explore sources of heterogeneity across included studies). | Uses a combination of meta-analytic and regression principles. |
Meta-summary [60] | To quantitatively aggregate qualitative findings. | Consists of extraction, grouping, abstraction, and formatting of findings and the calculation of frequency and intensity effect sizes. |
To transform qualitative data into few variables (numerical value) for statistical analysis. | Categorizes data and provides statistical description of the categories. | |
Vote counting [61] | To calculate the frequencies of categories of results across included studies. | The included studies are sorted into three categories (negative significant, positive significant, and statistically insignificant), and the number of studies for each category is calculated. The category with the most studies is the “winner.” |
Synthesis method | Aim | Description |
---|---|---|
Critical interpretive synthesis [62] | To build a theory from the synthesis of a diverse body of evidence. | Adapted the strategies of meta-ethnography (reciprocal translational analysis, lines-of-argument synthesis, and refutational syntheses) for qualitative and quantitative evidence. |
Framework synthesis [63] | To produce a new framework based on a priori and new themes. | Consists of analyzing data using an a priori framework, creating new themes by performing thematic synthesis, and producing a new framework. |
Grouping and clustering [44] | To describe included studies. | Summarizes and organizes included studies into groups (categories). |
Meta-ethnography [64] | To build a theory from the synthesis of qualitative studies. | Uses three main strategies: translating the concepts from studies into one another (reciprocal translational analysis), exploring and explaining contradictions between studies (refutational synthesis), and linking constructs and building a picture of the whole from studies (lines-of-argument synthesis). |
Meta-narrative synthesis [65] | To make sense of complex and conflicting findings by unfolding the storyline of research traditions. | Maps research traditions and consider how they have been conceptualized, theorized, and empirically studied over time. |
Meta-synthesis [66] | To understand a phenomenon of interest across qualitative studies. | Uses hermeneutic (portraying individual constructions) and dialectic (comparing and contrasting the constructions) approaches. |
Narrative synthesis [44] | To summarize and explain the findings of included studies. | Adopts a textual approach to the process of synthesis and follows four elements: develop a theory of how the intervention works, why, and for whom; develop a preliminary synthesis; explore relationships within and between studies; and assess the robustness of the synthesis. |
Qualitative content analysis [29] | To understand a phenomenon of interest by focusing on the manifest (patent) content or contextual meaning of text. | Uses an analytical coding process to organize content of textual data into fewer content categories. |
To unpack how interventions work in particular contexts through theoretical explanation (middle-range theory). | Uses theory-driven context-mechanism-outcome configurations, demi-regularities, and abduction (hunches). | |
Textual description [44] | To describe included studies. | Provides a descriptive paragraph of each study. |
Textual narrative synthesis [69] | To describe included studies. | Arranges studies into homogeneous groups and compares similarities and differences across studies. |
Thematic synthesis [70] | To identify and develop themes across included studies. | Uses line-by-line coding, develops descriptive themes, and generates analytical themes. This might lead to propose a conceptual framework. |
Results
Description of included reviews
Synthesis of results
Sequence and integration | |||||
---|---|---|---|---|---|
Synthesis | Convergent synthesis design | Sequential synthesis design | Total | ||
Data-based | Results-based | Parallel-results | |||
Qualitative | 69.5% | 6.3% | 12.0% | 2.6% | 90.4% |
Quantitative | 0.2% | 0% | 0% | 0% | 0.2% |
Mixed | 0% | 2.2% | 5.2% | 2.0% | 9.4% |
Total | 69.7% | 8.5% | 17.2% | 4.6% | 100% |