Towards the end of life, older people typically experience long periods of illness and complex fluctuations in their physical, social, psychological, and existential well-being. This ERC runner-up project will test and fine-tune high-risk components of an ERC proposal to lay the foundation for a ground-breaking mixed-method, inter-disciplinary investigation of these end-of-life trajectories. It responds to the long-standing scientific challenge of understanding what is generalisable and what is individually specific in older people’s end-of-life trajectories. This project will kickstart the development of a novel scientific framework, examining trajectories through two scientific lenses: a structured, quantitative method from the medical sciences to capture fluctuations in a standardised way, and an experience focused qualitative approach from the humanities to study the subjective stories behind changes in health. In a pilot convergent mixed-methods investigation, it combines a quantitative longitudinal study and a serial narrative interview study, with older people (≥70y) with chronic illness who are nearing the end of life. The findings of the two methods will be triangulated and systematically threaded together. This work will strengthen an ERC re-submission, which will lead to a fundamental re-thinking of how we examine, understand, and categorise end-of-life trajectories, and propel scientific advances towards achieving a good end of life in ageing societies.