This is a further analysis of a dataset originally generated for the following National Institute for Health Research Cochrane Programme Grant funded project: Hartmann‐Boyce J, Fanshawe TR, Lindson N, Livingstone‐Banks J, Ordóñez‐Mena JM, Aveyard P. Behavioural interventions for smoking cessation: an overview and network meta‐analysis. Cochrane Database of Systematic Reviews 2018, Issue 12. DOI: 10.1002/14651858.CD013229. In the original Cochrane review, we conducted a component network meta-analysis (cNMA), calculating effect sizes for individual components of behavioural smoking cessation support when compared to no smoking cessation intervention. The original analysis assumed additivity of component effects. In this analysis, we investigate whether this assumption is supported by data, focusing on combinations of components that have clinical and public health relevance. Thus, we will compare effects from the original additive model with those from an interactive model, allowing for non-additivity.