Development of workable solutions to overcome known limitations of overview methodology




Poster session 2


Monday 17 September 2018 - 12:30 to 14:00

All authors in correct order:

Broderick J1, Irving C2, Shokraneh F2, Ostinelli EG3, Walshe M1, Mockler D1, Adams C2
1 Trinity College Dublin, Ireland
2 University of Nottingham, UK
3 Department of Health Sciences, Università degli Studi di Milano, Italy
Presenting author and contact person

Presenting author:

Farhad Shokraneh

Contact person:

Abstract text
Overviews are a relatively new phenomenon borne out of the need to combine a number of systematic reviews for clinical decision making and policy development. Even though great strides have been made in overview methodology, considerable heterogeneity pertains to this form of evidence synthesis. For example, when to conduct a network meta-analysis versus an overview, decisions around selection criteria and assessment of quality of evidence. We propose workable solutions to these and other known limitations of overview methodology.

To generate workable solutions to known limitations of overview methodology.

We identified known limitations to overview methodology via an extensive search of literature pertaining to overview methodology and from hands-on experience of conducting an overview. Sensible, workable solutions have been proposed to methodological challenges of overviews that currently lack consensus, based on best evidence and application of sound reasoning.

We propose criteria that will aid in the decision-making process around the grey area of when to conduct a network meta-analysis versus an overview. We have discussed how harmonization of subsidiary reviews may need to take place before an overview can be undertaken. Our work outlines how Cochrane systematic reviews can be included preferentially, but have suggested how lower hierarchical forms of evidence can be searched and presented for hypothesis formation and identification of evidence gaps to produce a true 'bird's-eye' view of the topic area (Fig. 1). We have developed a search strategy to source all hierarchical forms of evidence (Table 1).

Overview methodology lacks consistency. We have developed workable solutions which will be tested through the 'hands on' experience of conducting an overview. We hope some solutions may be applied generically to future overviews, or, at the very least, may stimulate discussion around standardization of overview methodology.

Patient or healthcare consumer involvement:
There was healthcare consumer involvement in the production of subsidiary reviews to populate an overview which is currently under production. This overview is informing the development of generic methods outlined in this abstract.


Relevance to patients and consumers: 

Due to the proliferation of systematic reviews in recent years, overviews have been developed to collate systematic reviews and 'make sense' of different forms of treatment for example for the same condition. It is acknowledged that overview methods lack consistency. We outline workable solutions to known limitations of overview methodology. Harmonization and increasing the robustness of overview methodology would help make interpretation of overviews less difficult for clinicians, policy makers and ultimately patients and consumers and increase confidence in this useful form of evidence synthesis.