In this WIKI, three main types of mixed studies synthesis designs are presented: (1) sequential exploratory, (2) sequential explanatory, and (3) convergent.

The choice of the design depends on the review question(s). To see examples of review question(s) for each design, go to formulate a question.

In sequential exploratory synthesis, the qualitative synthesis is followed by, and informs, the quantitative synthesis; and the quantitative synthesis generalizes or tests findings of the qualitative synthesis. The integration occurs between the phases (phase-one qualitative necessary for phase-two quantitative), and for interpreting results of the second phase. In phase-one (qualitative), results of qualitative, quantitative and mixed methods studies are transformed into qualitative findings (e.g., types) using qualitative thematic analysis for instance. In phase-two (quantitative), results of quantitative studies are tabulated (pooled) and compared when there is a common entity across studies (e.g., an indicator for each type). Then, the interpretation of phase-one and phase-two results suggests new hypotheses and reveals knowledge gaps. 

Some mixed studies reviews that did a sequential exploratory synthesis: 

• Mills EJ, Seely D, Rachlis B, Griffith L, Wu P, Wilson K, et al. (2006). Barriers to participation in clinical trials of cancer: a meta-analysis and systematic review of patient-reported factors. The Lancet Oncology, 7(2), 141-148.
• Pluye P, Grad RM, Dunikowski LG, Stephenson R (2005). Impact of clinical information-retrieval technology on physicians: a literature review of quantitative, qualitative and mixed methods studies. International Journal of Medical Informatics, 74(9), 745-768.
• Rosewilliam S, Roskell CA, Pandyan AD (2011). A systematic review and synthesis of the quantitative and qualitative evidence behind patient-centred goal setting in stroke rehabilitation. Clinical Rehabilitation, 25(6), 501-514.

In sequential explanatory synthesis, the quantitative synthesis is followed by, and informs, the qualitative synthesis; and the qualitative synthesis helps to explain some results of the quantitative synthesis. The integration occurs between the phases (phase-one Quantitative is necessary for phase-two Qualitative), and for interpreting results of the second phase. In phase-one (quantitative), results of quantitative studies and quantitative results of mixed methods studies are tabulated (pooled in evidence tables) for instance, and the presence and importance of differences in effects are measured (e.g., using meta-analysis technique when appropriate). In phase-two (qualitative), findings of qualitative studies and qualitative findings of mixed methods studies are synthesized using qualitative thematic analysis for instance. Then, the interpretation of phase-one and phase-two results suggests new explication and reveals knowledge gaps.

Some mixed studies reviews that did a sequential explanatory synthesis: 

• Campbell F, Johnson M, Messina J, Guillaume L, Goyder E (2011). Behavioural interventions for weight management in pregnancy: A systematic review of quantitative and qualitative data. BMC Public Health, 11.
• Harden A, Brunton G, Fletcher A, Oakley A (2009). Teenage pregnancy and social disadvantage: systematic review integrating controlled trials and qualitative studies. British Medical Journal, 339, b4254.
• Thomas J, Harden A, Oakley A, Oliver S, Sutcliffe K, Rees R, et al. (2004). Integrating qualitative research with trials in systematic reviews. British Medical Journal, 328(7446), 1010-1012.

In convergent synthesis, results of included studies are complementary. The integration occurs for extracting and synthesizing these results using a transformation strategy. There are two categories of convergent synthesis design depending on the qualitative or quantitative nature of the data analysis: there is a qualitative synthesis or a quantitative synthesis of results of qualitative, quantitative, and mixed methods studies. In the data extraction for a qualitative synthesis, results of qualitative, quantitative, and mixed methods studies are transformed into themes such as constructs, concepts and factors. In the data extraction for a quantitative synthesis, results of qualitative, quantitative, and mixed methods studies are transformed into variables and values. 

Some mixed studies reviews that did a convergent qualitative synthesis: 

• Bélanger E, Rodríguez C, Groleau D (2011). Shared decision-making in palliative care: a systematic mixed studies review using narrative synthesis. Palliative Medicine, 25(3), 242-261.
• Lewis SA, Noyes J, Mackereth S, Lewis SA, Noyes J, Mackereth S (2010). Knowledge and information needs of young people with epilepsy and their parents: Mixed-method systematic review. BMC Pediatrics, 10, 103.
• Pedersen VH, Armes J, Ream E (2012). Perceptions of prostate cancer in Black African and Black Caribbean men: a systematic review of the literature. Psycho-Oncology, 21(5), 457-468.

Some mixed studies reviews that did a convergent quantitative synthesis:  

• Buelens M, Woestyne M, Mestdagh S, Bouckenooghe D (2008). Methodological issues in negotiation research: A state-of-the-art-review. Group Decision and Negotiation, 17(4), 321-345.
• Classen S, Lopez EDS (2006). Mixed methods approach explaining process of an older driver safety systematic literature review. Topics in Geriatric Rehabilitation, 22(2), 99-112.