In this new Series, we provide a platform for publishing insights that arise from synthesizing existing research on biological topics, along with papers describing relevant methods for such synthesis and meta-research studies that elucidate biases, gaps and opportunities in the biological literature. While this is not the first contribution of BMC Biology to the topic of research synthesis [1], we strongly feel it is timely and important to establish a dedicated Series focusing on research synthesis and related methods and topics. This is because, in biology, research synthesis such as meta-analysis is, so far, primarily embraced by disciplines such as ecology, evolution and biomedical sciences, but it will certainly benefit and interest researchers in other communities in life sciences. Thus, we are truly excited to open this Series to our authors and readers.
For a biologist, although it depends on the discipline, meta-analysis is probably the most familiar type of quantitative research synthesis [1, 2]. Some researchers, especially medical people, prefer using the terms ‘systematic review and meta-analysis’ or ‘systematic review and quantitative synthesis’ when they refer to a publication or study which includes a meta-analysis, which they consider to be simply the statistical analysis of material collected in a systematic review. Although these terms may be more descriptive, we feel they are a bit of a mouthful. Therefore, we use ‘meta-analysis’ as a shorthand for ‘systematic review with quantitative synthesis’ in Fig. 1, while we refer to ‘systematic review with qualitative synthesis’ (i.e., a review with qualitative interpretations offered) as ‘meta-synthesis’ [3]. Recent years have seen a marked increase in the range of approaches to systematic reviews [4], all based on a transparent, repeatable and rigorous procedure of literature search, screening and inclusion (at least in theory). This family of systematic reviews, for example, includes ‘rapid reviews’, a less comprehensive but quicker version of systematic reviews, and ‘systematic maps’ (also known as ‘evidence maps’), which catalogue related studies according to their characteristics (Fig. 1).
The members of the systematic review family are often collectively termed ‘evidence synthesis’ because they summarize the contents of related studies providing evidence for some phenomenon of interest. Another, very different, type of synthesis analyses, for instance, bibliometric information and other alternative metrics. We refer to this type as ‘influence synthesis’ to distinguish it from evidence synthesis [5]. To obtain a deeper and nuanced view of the relevant literature, it has been recently proposed to combine the use of the systematic review family with bibliometrics, such as performance analysis (e.g., total citations, h-index) and science mapping (e.g., citation networks, co-author networks). This novel methodological framework has been called ‘research weaving’ [5] because it weaves different components of research synthesis to give a richer fabric (Fig. 1). This new thematic section in BMC Biology will welcome not only any types of research syntheses, but also any associated methodologies. However, we especially welcome a synthesis or method of inter-disciplinary nature with broad significance.