RESUMO
OBJECTIVE: Learning about clinical trials is as stressful and challenging for cancer patients as it is for the clinical staff who provide education to patients. Information aids (IAs) can support both discussions and patients' decision-making, especially when IAs offer interactive features that provide information based on individuals' needs and experiences. However, it is not clear which factors contribute to interactive IAs' effectiveness. METHODS: An experiment with cancer patients and survivors (n = 313) compared the effects of two IAs about clinical trial participation: one with modality (i.e. website/technological) interactivity only and one with both modality and message interactivity (i.e. provides information contingent on individual users' information needs). RESULTS: The IA with both modality and message interactivity features elicited the higher perceived visual informativeness (PVI) and cognitive absorption (CA) scores. The model supports the moderating role of PVI and cancer information overload (CIO), and the mediating role of CA. CONCLUSION: The IA with both modality and message interactivity better supported individuals' decision-making and improved attitudes and knowledge scores. CIO was experienced more by participants using the modality interactivity-only IA. PRACTICE IMPLICATIONS: Message interactivity may simplify individuals' cognitive processes. IAs about clinical trial participation should include both message and modality interactivity.