In the first developmental phase, we will use existing daily life stress data from our studies to establish which contextual and person-specific factors play a key role in daily life stress, and which aspects of daily life stress responses should be prioritized for prolonged monitoring and for evaluation of (stress-)interventions. In parallel, starting from our existing arsenal of tools, we will develop methods to quantify daily life stress context and responses using smartphone-based ecological momentary assessments, accelerometer or other passive sensor-based tracking of behaviours, and physiological monitoring through wearables and non-invasive biomaterial sampling.

Human values and user-centred design take centre stage in the development of these new daily life stress assessment tools. Selection and validation pipelines in our design field labs establish their ethical and legal feasibility, user-acceptance, reliability and validity, and potential application in just-in-time adaptive stress interventions. In the second cohort enrichment phase, an increasingly better set of these tools will be applied to generate the most comprehensive dataset on daily life stress exposures and multicomponent stress responses to date. We enrich ongoing large-scale epidemiological cohorts with daily life stress assessments in at least 3000 participants across extended time periods and in multiple waves across years. These daily life stress assessments are linked to long-term follow-up of health outcomes.

For the ‘big data’ generated, improved data analytic strategies are developed combining a dynamic multilevel framework for prolonged and autocorrelated within-subject data with machine learning (ML)-based prediction strategies. In the model validation phase, our unique longitudinal dataset will allow rigorous testing of the growing theoretical framework for daily life stress and clinical utility of the stress-assessment toolkit. Through iterative experimental validation of theory and tools in ongoing and new interventions, we evaluate their potential to improve stress management and mental and cardiometabolic health.