Evaluation of a web-based educational program for women diagnosed with breast cancer: why is the intervention effect absent?

To provide accurate and tailored information to women diagnosed with breast cancer a web-based educational program was developed and tested in a randomized controlled trial for impact on health self-efficacy, healthcare participation, and anxiety and depression levels. Multilevel modelling with an intention-to-treat analysis revealed no treatment effect on the above-mentioned outcomes. Reasons for the non-identified effect are discussed and raise methodological questions concerning e-health supportive interventions for further research.