On Friday May 24th, my brilliant doctoral student Ellie Dillon defended her doctoral dissertation “Model-based approaches to decision making in healthcare delivery”. We had the great privilege of having Prof. Alec Morton from the University of Strathclyde to act as her honored opponent.
In the context of healthcare delivery, decision-making typically necessitates the consideration of many complicated aspects, including multiple objectives, large numbers of decision alternatives, and various uncertainties. In her thesis, Ellie argues that such complicated decisions can benefit from the use of mathematical modeling approaches. To illustrate this point, Ellie develops and applies (i) health economic evaluation methods to generate insights into improving the colorectal cancer screening programs in both Australia and Finland and (ii) two-stage stochastic programming methods to optimally manage the supply chain of blood products.
In the context of colorectal cancer screening, Ellie’s dissertation shows how model-based approaches can be used to identify those population segments that should be prioritized when resources for carrying out colonoscopies are strictly limited (due to, e.g., healthcare professionals being urgently needed in other tasks, as was the case during the COVID-19 pandemic). Here, model-based approaches help accommodate uncertainties related to the results of fecal immunochemical tests (i.e., false positives and negatives), which are used to refer people to colonoscopies, and the impacts that different constraints on the capacity to carry our colonoscopies have on test positivity thresholds.
In the context of the blood supply chain, model-based approaches can help develop optimal inventory management strategies under uncertain demand in view of minimizing operational costs, unmet demand, and expiry. The consideration of each of these objectives simultaneously is highly important in the case of blood products, which are not only highly important for maintaining people’s health (whereby unmet demand is highly problematic), but also voluntarily donated by ordinary people, whereby these products should not be wasted. In Ellie’s thesis, model-based approaches are used to generate optimal inventory strategies, and also to assess the impact of extending the shelf-life of platelets from five to seven days – a task which would be difficult without models.
It was wonderful to see Ellie defend her dissertation in an intellectual, mature way. I have thoroughly enjoyed this journey with Ellie, who is not only a brilliant researcher, but also a kind, caring, and funny human being ❤️