Theodore joined the Oxford Institute of Population Ageing in 2016 as a Research Fellow. He holds a Canadian Institute of Health Research Postdoctoral Fellowship, Simon Fraser University & University of Oxford 2016 – 2020 to conduct a project: “Resilience and healthy ageing across the life course: A multi-cohort longitudinal analysis of psychological wellbeing and physical adversity”. Supervisors: Professor Sarah Harper, Professor Andrew Wister. The project aims to examine early- and mid-life indicators of resilience and healthy ageing using data from the 1946 British Birth Cohort Study (MRC National Survey of Health and Development) and to contextualise these findings within a policy framework. 

Theodore is a Chartered Psychologist (British Psychological Society) trained in research methods (MSc, Trinity College Dublin) and epidemiology (PhD, University of Cambridge).

His primary areas of interest are in the positive aspects of ageing, e.g. resilience, applying longitudinal modelling techniques within a life course epidemiological framework, and the policy implications an ageing population.