Contrast-Based and Arm-Based Models for Network Meta-Analysis

Amalia Karahalios, Joanne E. McKenzie, Ian R. White

Research output: Chapter in Book/Report/Conference proceedingChapter (Book)Researchpeer-review

1 Citation (Scopus)


Network meta-analysis is used to synthesize evidence from a network of treatments. The models used in a network meta-analysis are more complex than those used for pairwise meta-analysis. Two types of models are available to undertake a network meta-analysis: contrast-based and arm-based models. Contrast-based models have been used in most published network meta-analyses. Arm-based models offer greater flexibility and handle treatments symmetrically, but risk compromising randomization. In this chapter, we (1) present the contrast-based and arm-based statistical models; (2) describe the theoretical differences between the models (noting when the estimates from the models are expected to diverge); (3) summarize the evidence comparing the two models from simulation studies and empirical investigations; and (4) provide a worked example applying the two models to a network using the R software package.

Original languageEnglish
Title of host publicationMethods in Molecular Biology
EditorsEvangelos Evangelou, Areti Angeliki Veroniki
Place of PublicationNew York USA
PublisherHumana Press
Number of pages19
ISBN (Electronic)9781071615669
ISBN (Print)9781071615652
Publication statusPublished - 2022

Publication series

NameMethods in Molecular Biology
PublisherHumana Press
ISSN (Print)1064-3745
ISSN (Electronic)1940-6029


  • Arm-based
  • Bayesian
  • Contrast-based
  • Mixed treatment comparisons
  • Models
  • Multiple treatments meta-analysis
  • Network meta-analysis
  • Systematic review

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