Synthesis involves combining the results of the studies included in the review, summarizing their findings and drawing reliable conclusions based on the quality of the evidence. Synthesis may be done quantitatively using statistical techniques, such as a meta-analysis, or through a narrative approach.
When preparing your report or article, refer to the PRISMA Checklist. Some commissioning bodies and journals have adopted PRISMA as the required methods for reporting systematic reviews.
For more information, see Chapter 6, Synthesizing the Evidence, in Systematic Reviews in the Social Sciences: A Practical Guide.