Welcome to the fourth newsletter for the Cochrane Statistical Methods Group

Issue 4 July 2025

Webinars for LMICs

The convenors of the SMG Group have launched a series of monthly webinars titled “Statistical Analysis in Systematic Reviews Series” These webinars are primarily designed for authors and trainers from low- and middle-income countries (LMICs) aiming to enhance their understanding of statistical methods in systematic reviews; however, participation is open to all. The webinars have already started, and many more will follow. Below are the scheduled webinars:

Upcoming webinars:

• Mark Simmonds will present the webinar Introduction to meta-analysis. Virtual Cochrane training webinar on Tuesday, 15 July 2025, 08:00-09:00 UTC.

• Theodoros Evrenoglou will present the webinar Exploring heterogeneity. Virtual Cochrane training webinar on Tuesday, 23 September 2025, 13:00-14:00 UTC.

• Areti Angeliki Veroniki will present the webinar Analysing other outcomes and study designs. Virtual Cochrane training webinar on Tuesday, 21 October 2025, 13:00-14:00 UTC.

• Jo McKenzie will present the webinar Synthesizing and presenting results when meta-analysis is not possible. Virtual Cochrane training webinar on Tuesday, 4 November 2025, 9:00-10:00 UTC.

Registration for each of the upcoming webinars is now open and free of charge. For more details about the courses and how to register, please click here.

Past webinars: 

• Joseph Alvin Ramos Santos, presented the webinar Dichotomous and continuous outcomes. Virtual Cochrane training webinar on Tuesday, 10 June 2025, 08:00-09:00 UTC. Total number of attendees: 238       

• Sue Brennan presented the webinar Defining a review question and applying the framework for synthesis. Virtual Cochrane training webinar on Monday, 19 May 2025, 10:00-11:00 UTC. Total number of attendees: 293     

All past webinars have been recorded and they are available here.

Webinar series

Upcoming webinars:

• Tianqi Yu will present the webinar An interactive online knowledge translation tool for network meta-analysis. Virtual Cochrane training webinar on Tuesday, 30 September 2025, 13:00-14:00 UTC.     

Register for the live event here. A full recording will be provided.

Past webinars:

• Jo McKenzie and Areti Angeliki Veroniki presented the webinar Demonstration of new random-effects methods in RevMan. Virtual Cochrane  training webinar on Tuesday 28 January, 2025. 

All past webinars have been recorded and they are available here.

Please do send us suggestions of presenters and topics for future learning live events.

RevMan updates

In September 2022, Cochrane endorsed the implementation of new statistical methods for random-effects meta-analysis. These methods have now been finalized, and the updated version of RevMan was released on January 23, 2025. In addition to the previously available implementations, the new RevMan version introduces the following features:

• the Hartung-Knapp-Sidik-Jonkman (HKSJ) method for calculating the confidence interval of the summary effect.

• the restricted maximum likelihood (REML) method (default option) for estimating the heterogeneity parameter.

• the Q-profile method for calculating the confidence interval of the heterogeneity estimate. 

• calculation of the I-square statistic using a new formula based on the heterogeneity estimate. 

• methods for calculating prediction intervals.

Publications

• Panagiotopoulou, K., Evrenoglou, T., Schmid, C. H., Metelli, S., & Chaimani, A. (2024). Meta-analysis models relaxing the random effects normality assumption: methodological systematic review and simulation study. arXiv preprint arXiv:2412.12945.

• Santos, JAR., Riggi, E. & Di Tanna, GL (2025). Warnings on the inclusion of cluster randomized trials in meta-analysis: results of a simulation study. BMC Medical Research Methodology 25(133). https://doi.org/10.1186/s12874-025-02586-2.

• Lunny C, Higgins J, White I, Dias S, Hutton B, Whiting P, Veroniki AA, Wright JM, Tricco AC. RoB NMA Explanation and Elaboration: Development of a tool to assess risk of bias (RoB) in network meta-analysis (NMA). BMJ. 2025:388:e079839 https://pubmed.ncbi.nlm.nih.gov/40101916/.

• Karahalios A, White IR, Turner SL, Salanti G, Herbison GP, Veroniki AA, Nikoakopoulou A, McKenzie JE. An investigation of the impact of using contrast-based and arm-based synthesis models for network meta-analysis. Research Synthesis Methods. Published online 2025:1-19. doi:10.1017/rsm.2025.18 https://www.cambridge.org/core/journals/research-synthesis-methods/article/an-investigation-of-the-impact-of-using-contrast-and-armsynthesis-models-for-network-metaanalysis/8211C05BD2A2E70CE0742EFC70B23EF4.

• Veroniki AA, Wolfe D, Hutton B, Schwarzer G, Straus SE, Jackson D, Tricco AC. Analysing complex interventions using component network meta-analysis https://www.medrxiv.org/content/10.1101/2025.06.30.25330567v1.

SMG presence on social media

• We are happy to announce that SMG Group has launched new pages on LinkedIn (https://www.linkedin.com/groups/14581838/) and Bluesky (https://bsky.app/profile/cochranesmg.bsky.social). These platforms will serve as our primary channels for sharing updates. As part of our transition, we have decided to discontinue our account on X (formerly Twitter). This account will no longer be updated.

Contact us

Convenors: 

Joanne McKenzie, Australia
Mark Simmonds, UK
Areti Angeliki (Argie) Veroniki, USA

Theodoros Evrenoglou, Germany

Joseph Santos, Switzerland

Lizzie Korevaar, Australia

For details about how to post to the SMGlist, or how to unsubscribe from the list, please go to: https://lists.cochrane.org/mailman/listinfo/smglist