Article type
Year
Abstract
Background:
Since their emergence in the 1980s, systematic reviews (SRs) have been the cornerstone of evidence-based medicine (EBM). They are less likely to be biased than narrative reviews (NRs), though NRs are historically more established among the medical community. A previous study comparing both review types found that, in numbers, the NR is by far the dominating type of review to be published, concluding that “journal publishing of non-systematic reviews […] has far outstripped the growth of SRs” (Bastian 2010).
Objectives:
We aimed to find out whether the advent of EBM is reflected in SRs having a larger increase in publication rates than NRs - are SRs beginning to draw level with NRs in terms of growth in publishing numbers?
Methods:
We conducted a literature search in MEDLINE in 2013 to assess the number of published NRs and SRs from 1990 to 2012. We used a filter to identify the number of SRs and then subtracted this number from the number of all publications indexed with the tag ‘review’ to obtain the number of NRs. The retrieved references were grouped according to year of publication and their numbers fitted to a parabola, with the quadratic term year² indicating whether the increase is declining or growing.
Results:
Our analysis shows that from 1990 to 2012, the increase in number of published NRs per year is clearly slowing down (P value < 0.001), while the numbers of published SRs indicate an accelerated growth (P value < 0.001), thus confirming our hypothesis that SRs show a larger increase in publication rates than NRs. This leads to some alignment in publishing numbers: For instance, in 2004, the number of published NRs was approx. 14 times the number of published SRs, whereas the same ratio was approx. 5 in 2012 (Fig. 1).
Conclusions:
We agree with Bastian 2010, in that the staple of medical literature synthesis remains the non-systematic NR. However, our results also suggest a trend towards the SR as the scientific community’s preferred type of review: growth in published SRs is now exceeding growth in published NRs, which might eventually lead to the SR drawing level with the NR in terms of publishing numbers.
Since their emergence in the 1980s, systematic reviews (SRs) have been the cornerstone of evidence-based medicine (EBM). They are less likely to be biased than narrative reviews (NRs), though NRs are historically more established among the medical community. A previous study comparing both review types found that, in numbers, the NR is by far the dominating type of review to be published, concluding that “journal publishing of non-systematic reviews […] has far outstripped the growth of SRs” (Bastian 2010).
Objectives:
We aimed to find out whether the advent of EBM is reflected in SRs having a larger increase in publication rates than NRs - are SRs beginning to draw level with NRs in terms of growth in publishing numbers?
Methods:
We conducted a literature search in MEDLINE in 2013 to assess the number of published NRs and SRs from 1990 to 2012. We used a filter to identify the number of SRs and then subtracted this number from the number of all publications indexed with the tag ‘review’ to obtain the number of NRs. The retrieved references were grouped according to year of publication and their numbers fitted to a parabola, with the quadratic term year² indicating whether the increase is declining or growing.
Results:
Our analysis shows that from 1990 to 2012, the increase in number of published NRs per year is clearly slowing down (P value < 0.001), while the numbers of published SRs indicate an accelerated growth (P value < 0.001), thus confirming our hypothesis that SRs show a larger increase in publication rates than NRs. This leads to some alignment in publishing numbers: For instance, in 2004, the number of published NRs was approx. 14 times the number of published SRs, whereas the same ratio was approx. 5 in 2012 (Fig. 1).
Conclusions:
We agree with Bastian 2010, in that the staple of medical literature synthesis remains the non-systematic NR. However, our results also suggest a trend towards the SR as the scientific community’s preferred type of review: growth in published SRs is now exceeding growth in published NRs, which might eventually lead to the SR drawing level with the NR in terms of publishing numbers.