Ronan is an epidemiologist with 30 years experience of clinical medicine, public health and health informatics in Ireland and the UK. He is currently Professor of Public Health at Swansea University, having moved from a personal chair in Public Health Medicine at Cardiff University in 2005. He has a long history of involvement in health informatics since the 1990s. Along with his colleague, David Ford, he developed and co-directs the Health Information Research Unit (HIRU), core funded by Welsh Government through the National Institute of Health and Social Care Research (NISCHR), and actively supported by NHS Wales. HIRU created the Secure Anonymised Information Linkage (SAIL) system, the national e-health records research facility for Wales, which now supports more than 50 research  projects. 

He has considerable experience of leading and participating in successful complex, multidisciplinary, multi-university collaborations.  He led the Swansea/Nottingham/UWE-Bristol/Surrey consortium of universities for the Department of Health funded injury programme: Moving from Observation to Intervention (MOI) to reduce inequalities in injuries (2004-2010), and is Co-Director and Swansea University lead for the Cardiff/Bristol/Swansea UKCRC funded DECIPHer Centre of Excellence for Public Health Research (2009-2013). He is a named investigator on a number of multi-centred grants, including the ESRC/HEFCW funded Wales Institute for Social and Economic Research: Data and methods (WISERD) centre (2008-2012); the Wellcome Trust funded PEARL study; the multi-funder(ESRC led) UK Birth Cohort Study due to start in 2012; and is a member of the UK Biobank Longitudinal Follow Up Group. He is involved in several multi-disciplinary collaborations using e-health data to evaluate natural experiments, including the NIHR funded evaluations of improving housing quality (http://www.phr.nihr.ac.uk/funded_projects/09_3006_02.asp) and the influence of changing exposure in alcohol outlet density on measures of alcohol related harm (http://www.phr.nihr.ac.uk/funded_projects/09_3007_02.asp). He leads the NISCHR funded total population anonymised e-cohort, Wales Electronic Cohort for Children, which has been assembled from eight different datasets and currently includes 801,000 children born since 1990. 

Within the field of injury epidemiology and prevention he developed the All Wales Injury Surveillance System (AWISS) and has been involved in a number of EU funded projects, including, currently, the JAMIE project (Joint Action on Monitoring Injuries in Europe).  He is a scientific advisor to the EU TACTICS project (Tools to Address Childhood Trauma, Injury and Children's Safety), the NIHR programme grant "Developing new ways of measuring the impact of ambulance service care" led by Siriwardena (East Midlands and Sheffield), and the Canadian Institute of Health Research's Team in Child and Youth Injury Prevention "Strategic Teams in Applied Injury Research", led by Pike (University of British Colombia). He hosted the Swansea Injury Forum in 2010 on behalf of the International Collaborative Effort on Injury Statistics and the Global Burden of Diseases Injury Expert Group, attended by 60 delegates from 24 countries, with many form low income countries receiving support from the World Health Organization or World Bank. 

His expertise in health informatics was recognised by a personal invitation to be a member of the OSCHR E-Health Records Research Board and External Reference Group of the Research Capability Programme during their lifespan from 2007-2009. He has given a number of  key note presentations , including  "Optimising the use of Routine Data in Public Health Evaluation", at the annual meeting of the five UKCRC Centres of Excellence for Public Health Research in Belfast in 2011.