Andrew has expertise in all areas of health economic evaluation -- he has published over 300 articles in the peer-reviewed literature. He has particularly focused on statistical methods for cost-effectiveness analysis. This includes statistical methods for estimation of parameters for cost-effectiveness models as well as statistical analysis of cost-effectiveness alongside clinical trials. He also has a more general interest in epidemiological methods, in particular the use of prognostic scoring methods for predicting health outcomes and the relationship with heterogeneity in cost-effectiveness.

Andrew took a leadership role as co-chair of the Joint Society for Medical Decision Making (SMDM) and International Society for PharmacoEconomics and Outcomes Research (ISPOR) Task Force on Modelling Methods. The Task Force, which was responsible for producing a set of seven papers covering all aspects of modelling methods applied to medical decision making and health technology assessment. He is also the author of two successful textbooks, one published by OUP entitled Decision Modelling for Health Economic Evaluation, and another published by Wiley entitled Statistical Methods for Cost-Effectiveness Analysis.