The synthesis of expert opinion findings within the systematic review process is not well recognized in mainstream evidence-based practice and it is acknowledged that efforts to appraise often conflicting opinions are tentative. However, in the absence of research studies, the use of a transparent systematic process to identify the best available evidence drawn from text and opinion can provide practical guidance to practitioners and policy makers. “Textual evidence should be understood as the narrative expression of clinical wisdom from health professionals.” (Jordan, Konno & Mu, 2011, p.19) It may also draw on the expertise of consumer representatives that are aligned with affiliated organizations.
For some clinical questions, there is an absence or paucity of quantitative and/or qualitative research studies, and in these situations, textual evidence can be promoted to understand narratively expressed experiences/tacit knowledge on a topic of interest. Textual evidence is, according to Mattingly (1991) and Worth (2008), the narrative expression of clinical wisdom from health professionals. Narrative knowledge does not fall into a conventional academic reasoning system of induction and deduction, but it is possible that health professionals can receive content-specific guidance and insights into how to improve their everyday practice based on the synthesis of textual evidence. This may also relate to the current discourse, or the verbal interchange of ideas that is grounded in language and in the context within which it occurs. Discourse in the professional and public domains is a source of knowledge that can be used to inform policy and clinical decision making.
When would you undertake a systematic review of text and opinion?
There are broadly three indications for undertaking a review of text and opinion.
As an adjunct to a quantitative or qualitative review where there are no research studies identified.
As an adjunct to a comprehensive systematic review, where the text and opinion component may provide supplemental evidence to the quantitative or qualitative reviews. An example of this is a comprehensive systematic review conducted on the best evidence for assisted bathing of older adults with dementia (Konno et al, 2013).
As a stand alone review to investigate:
People’s opinions/thoughts/conclusions
Discourse analysis
Policy analysis (an example of this is a systematic review looking at local and national policy and practice initiatives in relation to maternal mortality. McArthur & Lockwood, 2013))
The nature of textual or opinion based reviews is that they do not rely upon evidence in the form of primary research and, therefore, elements of the protocol will vary from reviews drawing on primary research as the types of papers of interest. However, the principals of developing a clearly documented protocol, incorporating a priori criteria and methods are – as for any systematic review – considered essential.