Our Core Functions

Providing policy advice

CMIMG will maintain and develop guidance for (i) Overviews of reviews and (ii) use of multiple treatments meta-analysis methods, for inclusion in the Cochrane Handbook for Systematic Reviews of Interventions.

Cochrane Overviews are expected to follow the methodology described in the current Handbook chapter on Overviews, and will provide valuable experience to enable the Methods Group to determine the strengths and weaknesses of the initial methodology. A full list of the completed overviews  and protocols currently published in The Cochrane Library, is available here. In addition, the first conventional intervention review (to our knowledge) to incorporate a formal MTM was recently published (Fluoride toothpastes of different concentrations for preventing dental caries in children and adolescents). Members of the methods group are also engaged in providing statistical and methodological advice to Cochrane Review Groups on the use of MTM.  There is a clear need to clarify the role of MTM in Overviews and in conventional reviews,building on the experience being gained of using MTM in Cochrane reviews, and to co-ordinate the methods advice to ensure methodological consistency and transparency across both types of Cochrane reviews.

Members of the Methods Group wrote the Overviews chapter and the material on MTM in the current Handbook. They also have pioneered advances in MTM methodology and have a strong track record of research in the area. A principal aim of the Methods Group is to develop detailed guidance for Cochrane review authors to draw on the expertise of Cochrane methodologists. The Methods Group works with the Cochrane Methods Board to establish methodological policies for the Collaboration, and with the Handbook Editorial Advisory Panel and the RevMan Advisory Group to ensure appropriate implementation of this policy.

Serving as a forum for discussion

The Methods Group has begun and will keep up-to-date a list of its members, detailing their areas of interest and expertise, and will maintain an email discussion list as a forum for discussing relevant methodological issues.

We hope that this web page will allow us to disseminate up-to-date developments in this rapidly evolving research field and will help interaction with individuals and Cochrane entities. Annual meetings at Colloquia and national meetings of the Collaboration will also be scheduled. Finally,the proposed CMIMG will provide a point of contact for Cochrane Review Groups interested in undertaking an Overview, with or without MTM, or a MTM in a conventional Intervention review. A mailing list will be established among the interested individuals.

Ensuring that the group functions as part of the Cochrane Collaboration

The Methods Group follows similar procedures to existing Methods Group to ensure that it participates fully in the Collaboration.

The CMIMG has representation in the Methods Board, will maintain this web site, keep details on Archie up to date,participate in the monitoring process and work towards sustainability of the Methods Group. The Methods Group has started with a six Co-Convenors, who will be on rolling three-year appointments to ensure they remain appropriate to the position.

Optional Core Functions

Providing training

The Methods Group will take responsibility of training activities at Colloquia and training material will be made publicly available by contributing it to the Training Working Group's central training resource.

MTM training workshops have been run by members of the Statistical Methods Group for four years, with the first workshop being held at the 14th colloquium in Dublin (Salanti, Caldwell & Higgins). In 2009 the growth of interest in MTM and its application in Overviews led to the workshop being split into three - basic (Becker, Thomson & Caldwell), intermediate (Caldwell & Salanti) and advanced (Salanti, Caldwell & Higgins), and these workshops were repeated at the Keystone Colloquium in 2010. Workshops at national Cochrane meetings have also been held for several years - for example, at UK & Ireland contributors meetings (Caldwell), at various branches of the Iberoamerican Cochrane Center (Salanti), at the 3rd South Asian Symposium organized by the South Asian Cochrane Center (Salanti).  A list of the workshops is presented on our "Workshops and Presentations" pages. Workshops similar in nature and target audience will be organized in Cochrane Colloquia and regional meetings, and training needs will be reviewed yearly.

Providing peer review

The Methods Group will assist with peer reviewing Cochrane reviews addressing multiple interventions. We would like to explore processes for registering planned Overviews with the CMIMG.

CRGs are strongly encouraged to contact the CMIMG as soon as they register an Overview title and draw on the experience of other CRGs who are preparing or developing protocols for Overviews. The Methods Group can support this process by assigning (if possible and relevant)a member of the group knowledgeable in Overviews methodology and MTM techniques.

Providing specialist advice

The Methods Group will provide specialist advice where feasible.

MTM analyses are complicated and typically require specialist expertise, and members of the proposed Methods Group are in principle willing to provide advice to review teams and CRGs. We recognise,however, that this function could be resource intensive once MTM is used more regularly within Cochrane reviews and it will be important to keep this function under review. The Methods Group are collating a list of methodologists (including statisticians) who are willing to be involved in supporting, reviewing and advising on reviews that compare multiple interventions. Specialist advice will include statistical issues and methodological considerations regarding the evaluation of evidence, the risk of bias and updating procedures. Support will typically be in return for co-authorship.

Contributing to software development

CMIMG will explore several software options to facilitate Overviews of Reviews and MTM

Currently the majority of applied MTM papers have used Bayesian approaches as these methods allow for greater complexity and flexibility of modelling than traditional frequentist approaches. Software limitations are a key obstacle to the use of MTM in Cochrane Overviews, and options need to be explored in collaboration with the RevMan Advisory Committee. Members of the group are well-placed to provide this support.

Further activities

While not registering them as core functions, the Methods Group will fulfil several other functions on an informal basis.

Methodological research: Members of the proposed Methods Group account for the majority of both methodological and applied research onMTM (See Appendix). Landmarks include the first paper to describe the approach that has become the standard for Bayesian MTMs (Higgins and Whitehead 1996) and a methodological presentation at the Cochrane Colloquium in Melbourne in 2005for which G. Salanti won the Thomas Chalmers award for the best oral presentation. Many methodological papers and posters are now presented at Cochrane Colloquia each year.

As MTM is an emerging technique, there are several methodological issues that still need to be addressed. The Methods Group will identify them to motivate further research. A preliminary list of areas for further research are: determining how wide to cast the net in terms of which interventions to include in a review or MTM; strategies for evaluating whether the evidence is consistent, and what to do if it is not; the role of study-specific bias and reporting bias; and adjustment for study-level covariates.

Compiling existing research: Members of the Methods Group have collated methodological papers about indirect comparisons, MTM and related topics. We plan to update these lists at least once a year. These will be forwarded to the Cochrane Methodology Review Group for potential inclusion in the Methodology Register.