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. 

He has an MSc in Statistics and is an Editor for HPB. His work is funded by the NIHR, Wellcome Trust, MRC and Academy of Medical Sciences. He has given the British Journal of Surgery Lecture 2017 at the 12th annual Academic Surgical Congress, the Honyman Gillespie Lecture 2016m and the Macewan Lecture 2016 at the Association of Surgeons of Great Britain and Ireland. He has recently completed a James IV Travelling Fellowship UK and Davies Travelling Fellowship in Sub-Saharan Africa and North America. 

He is the Programme Director for the Masters in Surgery degree at the University of Edinburgh - a distance learning qualification which allows surgeons to train while continuing to work in their home country.

In 2023 he was awarded an OBE for services to the Covid-19 response, he was elected a Fellow of the Royal Society of Edinburgh and a Fellow of the Academy of Medical Sciences.

• Bachelor of Medicine and Bachelor of Surgery (MBChB commendation) June 1999, University of Glasgow
• Doctor of Philosophy (PhD) July 2008. "Pharmacological strategies to reduce ischemi-reperfusion injury in kidney transplantation", University of Edinburgh
• Fellow of the Royal College of Surgeons (FRCS Gen surg) June 2011. Sub-specialty exam: transplantation, Royal College of Physicians and Surgeons of Glasgow
• Graduate Certificate in Mathematics and Statistics, University of Sheffield, June 2012
• MSc Statistics with Medical Applications, University of Sheffield, November 2015