All in the Family: systematic reviews, rapid reviews, scoping reviews, realist reviews, and more. Moher D et al. Systematic Reviews 20154:183

The journal Systematic Reviews has been responsible for a significant number of the articles on rapid review methods featured on this site.  This latest article, an editorial, is refreshing!  It helpfully restates the role of systematic reviews and highlights the methodological development:

“What distinguished systematic reviews was the use of formal explicit methods, in other words pre-specification, of what exactly was the question to be answered, how evidence was searched for and assessed, and how it was synthesized in order to reach the conclusion. Importantly, these formal methods were described as part of the review itself in a Methods section. In turn, these methods themselves became the subject of hypothesis-testing studies…”

They then discuss the rise of rapid, scoping and other forms of reviews stating:

“It is our view that all of these new forms of reviews are related to systematic reviews, similar to the way that different biological Species within the same Family are related to each other.”

I like the notion of a systematic review ‘family’ but it still requires further development of the nomenclature.  When you think of a ‘systematic review’ it probably evokes images of Cochrane-style systematic reviews.  Is this the standard measure of a systematic review?  Is a systematic review using regulatory data, unpublished trials etc a systematic review plus?  What about one using rapid methods – is that a rapid review or a rapid systematic review?  It’s confusing for me and I dare say it is for consumers of evidence who, if they are trained in evidence-based method see systematic reviews as being at the top of the evidence pyramid.  But this issue is for further discussion!

The final paragraph was particularly notable:

“Systematic Reviews has responded to these emerging techniques and already publishes papers reporting methods and findings from the systematic review family and has for example published an extremely popular series on rapid reviews. We would like to consolidate this position and invite submission of these new species of reviews, as long as they meet the qualifications just listed. We expect this process of evolution to continue and to refine the methods such that in 10 years’ time, there will appear new, as yet unimagined species of reviews—and perhaps some current species of review will become extinct. Thus, it is with the scientific method, which we believe is the foundation that unites the Family of systematic reviews.”

The editors are looking forward, expecting change and opening up the possibility that certain methods might actually be extinct.  It is so nice to see this last paragraph, it brings with it a great sense of optimism.