Research synthesis is the process of combining the results of multiple primary research studies aimed at testing the same conceptual hypothesis. It may be applied to either quantitative or qualitative research. Its general goals are to make the findings from multiple different studies more generalizable and applicable.
Meta-analysis is the preferred technique of quantitative research synthesis in many fields, such as medical science. This technique can sometimes accurately estimate an overall effect, but it may suffer from limitations when there is variation in the included studies with regard to study design, the type of evidence, or other key characteristics. Methods of qualitative research synthesis include narrative synthesis and meta-ethnography. Narrative synthesis allows researchers to address a wide range of questions in their review, while meta-ethnography aims to preserve the cultural context in which the original findings of the included studies were generated. The narrative synthesis approach has attracted criticism because of its potential for bias, with critics highlighting the subjective nature of the use of the method to draw conclusions. There is also evidence that reviews using the narrative synthesis approach often suffer from a lack of transparency.
- Hall, Judith A.; Tickle-Degnen, Linda; Rosenthal, Robert; Mosteller, Frederick (1993-11-23). "Hypotheses and Problems in Research Synthesis". In Cooper, Harris; Hedges, Larry V. (eds.). The Handbook of Research Synthesis. Russell Sage Foundation. ISBN 9781610441377.
- Suri H (2011-08-03). "Purposeful Sampling in Qualitative Research Synthesis". Qualitative Research Journal. 11 (2): 63–75. doi:10.3316/QRJ1102063. ISSN 1443-9883.
- Wyborn C, Louder E, Harrison J, Montambault J, Montana J, Ryan M, Bednarek A, Nesshöver C, Pullin A (August 2018). "Understanding the Impacts of Research Synthesis". Environmental Science & Policy. 86: 72–84. doi:10.1016/j.envsci.2018.04.013.
- Denyer D, Tranfield D, van Aken JE (March 2008). "Developing Design Propositions through Research Synthesis". Organization Studies. 29 (3): 393–413. doi:10.1177/0170840607088020. ISSN 0170-8406.
- Barnett-Page E, Thomas J (August 2009). "Methods for the synthesis of qualitative research: a critical review". BMC Medical Research Methodology. 9 (1): 59. doi:10.1186/1471-2288-9-59. PMC 3224695. PMID 19671152.
- Campbell M, Katikireddi SV, Sowden A, Thomson H (January 2019). "Lack of transparency in reporting narrative synthesis of quantitative data: a methodological assessment of systematic reviews". Journal of Clinical Epidemiology. 105: 1–9. doi:10.1016/j.jclinepi.2018.08.019. PMC 6327109. PMID 30196129.