The Journal Research Synthesis Methods has published a Special Issue on Network Meta-analysis - edited by Georgia Salanti and Christopher Schmid. 

The following excerpt from the editors introduction to the issue gives a brief description of the contents.

"The special issue starts with a review by Asmaa Abdelhamid and colleagues of the perceptions of Cochrane reviewers regarding indirect comparison and related methods. The next article by the issue editor, Georgia Salanti, is a tutorial providing a very detailed presentation of the assumptions underlying the methods and their major advantages and limitations. Julian Higgins and colleagues provide a novel model for testing and accounting for violations in consistency, the key assumption underlying network meta-analysis. Ian White and colleagues show how network meta-analysis can be fit in frequentist setting using stata software (StataCorp, TX, USA), a development sure to have a major impact on application of the method. Two papers address more technical questions. Deborah Caldwell and colleagues address the association between the choice of effect size for dichotomous data and the consistency of evidence, whereas Angelo Franchini and colleagues study the importance of accounting for the correlations induced by multi-arm trials. The special issue closes with two important extensions of the network meta-analysis model. The article by Anna Chaimani and colleague shows how small study effects (the phenomenon that small studies appear to exaggerate relative treatment effects) can be accounted for in a dataset comparing many competing interventions. Finally, Jeroen Jansen extends the network meta-analysis model to synthesize information from individual patient data and aggregated data."