Ewen is Professor of Surgery and Data Science at the University of Edinburgh and a Consultant HPB and Transplant Surgeon at the Royal Infirmary of Edinburgh. 

Interests include crowd-sourcing patient-level date; surgical trials, particularly in low resource settings; mobile data collection platforms and "wearables"; automated data processing and display; natural language processing/sentiment analysis; decision modelling; Bayesian statistics; administrative data analysis; and patient reported outcomes.

He leads the NIHR Unit on Global Surgery at the University of Edinburgh, a collaboration with the Universities of Birmingham and Warwick. This provides a patform for the GlobalSurg Collaborative (globalsurg.org), an international collaboration of 5000 individuals in 420 centres across 102 countries studying outcomes in general surgery and quality improvement.