Initial validation of the 'Susceptibility to Purchasing Illicit Tobacco (SPIT)' scale

This study aims to establish whether ‘susceptibility’ constitutes a coherent higher-order latent disposition suitable for future applications. Confirmatory analyses test the proposed subscale structure and higher-order specification, while exploratory analyses assess dimensional robustness and construct boundaries. The core objective is scale validation, while also ensuring that subsequent moderation analyses, using validated ‘SPIT’ indicators, reflect substantive behavioural heterogeneity rather than measurement artefact.