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Dr. James O'Mahony
Visiting Adjunct Assistant Professor, Public Health & Primary Care
Visiting Adjunct Assistant Professor, Histopathology


Dr O'Mahony holds a BA in economics and philosophy from Trinity College Dublin, an MA in economics from University College Dublin and a PhD from Trinity College Dublin. He has always been interested in the way that economics influences public policy and has worked in the field of health economics since 2008. James was awarded a Health Economics Fellowship by Ireland's Health Research Board (HRB) and he undertook a PhD on the cost-effectiveness of cancer screening. During his doctoral research James spent two years at the Department of Public Health at the Erasmus Medical Centre at Rotterdam, the Netherlands. During his time there James worked with the MISCAN microsimulation model of cancer prevention. His thesis concerned methodological questions in cost-effectiveness analysis (CEA), primarily relating to the fit of CEA models to policy questions. James spent the final year of his PhD studies working as an intern at the Health Information and Quality Authority (HIQA), where he contributed to both the organisation's Budget Impact Analysis (BIA) guidelines and to a CEA of breast screening for women of above average risk of disease. James is a Research Assistant Professor at the Centre for Health Policy and Management at Trinity College Dublin. He is employed under an Emerging Investigator Award, funded by the Health Research Board. His research retains a focus on CEA methods in cancer screening but also includes work on the cost-effectiveness threshold and CEA methods more broadly. James has close research links with collaborators internationally and is a member of several international research consortia. He is a member of the editorial board of the journal PharmacoEconomics and is an active reviewer for other journals. He teaches on a number of courses including the HRB-sponsored Stuctured Population and Health-Sevices Research Education (SPHeRE) programme. He also provides PhD supervision to doctoral, masters level and undergraduate students. James is a member of Ireland's National Screening Advisory Committee convened following the Scally Report in response to the CervicalCheck controversy.

Publications and Further Research Outputs

Peer-Reviewed Publications

O'Mahony JF, Risk Stratification in Cost-Effectiveness Analyses of Cancer Screening; Intervention Eligibility, Strategy Choice, and Optimality, Journal of Medical Decision Making, 2021 Journal Article, 2021 URL DOI

O'Mahony, JF, van Rosmalen, J, Mushkudiani, NA, Goudsmit, F-W, Eijkemans, MJ, Heijnsdijk, EA, Steyerberg E & Habbema, JDF, The Influence of Disease Risk on the Optimal Time Interval between Screens for the Early Detection of Cancer A Mathematical Approach, Medical Decision Making, 2014 Journal Article, 2014 Other DOI URL

van Rosmalen, J, Toy, M, & O'Mahony, JF, A Mathematical Approach for Evaluating Markov Models in Continuous Time without Discrete-Event Simulation, Medical Decision Making, 33, (6), 2013, p767 - 779 Journal Article, 2013 DOI URL URL

Almajed S, Alotaibi N, Zulfqar S, Dhuhaibawi Z, O'Rourke N, Gaule R, Byrne C, Barry AM, Keeley D, and O'Mahony JF, Cost-efectiveness evidence on approved cancer drugs in Ireland: the limits of data availability and implications for public accountability, The European Journal of Health, 2021 Journal Article, 2021 DOI URL

O'Mahony JF, Revision of Ireland's Cost-Effectiveness Threshold: New State-Industry Drug Pricing Deal Should Adequately Reflect Opportunity Costs, PharmacoEconomics, 2021 Journal Article, 2021 DOI URL

O'Mahony, JF, & Paulden, M, NICE's Selective Application of Differential Discounting: Ambiguous, Inconsistent, and Unjustified, Value in Health: The Journal of The International Society for Pharmacoeconomics and Outcomes Research, 17, (5), 2013, p493 - 496 Journal Article, 2013 Other DOI URL

O'Mahony, JF, Cost-effectiveness of population-based screening for colorectal cancer, British Journal of Cancer, 108, (5), 2013, p1209 - 1210 Journal Article, 2013 URL DOI Other

O'Mahony JF, Newall AT, and van Rosmalen J, Dealing with Time in Health Economic Evaluation: Methodological Issues and Recommendations for Practice, PharmacoEconomics, 2015, pDOI 10.1007/s40273-015-0309-4 Journal Article, 2015 Other URL DOI

O'Mahony, JF., van Rosmalen, J, Zauber, AG and van Ballegooijen M, Multicohort Models in Cost-Effectiveness Analysis Why Aggregating Estimates over Multiple Cohorts Can Hide Useful Information, Medical Decision Making, 33, (3), 2013, p407 - 414 Journal Article, 2013 URL Other DOI

O'Mahony, JF, de Kok, IMCM, van Rosmalen, J, Habbema, JDF, Brouwer, WBF and van Ballegooijen, M, Practical implications of differential discounting in cost-effectiveness analyses with varying numbers of cohorts, Value in Health: The Journal of The International Society for Pharmacoeconomics and Outcomes Research, 14, (4), 2011, p438 - 442 Journal Article, 2011 DOI URL Other

Paulden, M and O'Mahony, JF, Why the National Institute for Health and Care Excellence's New Guidance on Discounting Creates Scope for Age Discrimination and other Inconsistencies, Bench, Bedside and Beyond: Medical Decision Making and Public Policy, Baltimore, MD, USA, October 19-23, 2013, 2013 Oral Presentation, 2013 URL

O'Mahony, JF, Postma, MJ, Boersma, C, Westra, TA, van Rosmalen, J and Jit, M, Correcting for Multiple Future Cohorts When Applying Differential Discounting of Costs and Health Effects, 14th Biennial SMDM European Meeting, Olso, Norway, June 10-12, 2012, 2012 Oral Presentation, 2012 URL

O'Mahony, JF and O'Neill, C, The Health of Health Technology Assessment in Ireland: Five Points for Improvement, ISPOR 16th Annual European Congress, Dublin, Ireland, November 2-6, 2013, 2013 Poster, 2013 URL

O'Mahony, JF and Paulden, M, NICE's Selective Application of Differential Discounting: Ambiguous, Inconsistent and Unjustified, ISPOR 18th Annual International Meeting; Patient-Centered Outcomes: Focusing on the Patient, New Orleans, LA, May 18-22, 2013, 2013 Poster, 2013 URL

O'Mahony, JF, van Rosmalen, J and van Ballegooijen, M, Multiple Cohort Modelling of Long-Duration Interventions: Questioning Time Horizons and Aggregation Across Cohorts, ISPOR 13th Annual European Congress, Prague, Czech Republic, November 6-9, 2010, 2010 Oral Presentation, 2010 URL

O'Mahony, JF, Naber, S and de Kok, IMCM, A Critical Appraisal of Cost-Effectiveness Analyses of Human Papillomavirus Testing in Cervical Screening: Making Appropriate Comparisons and Usefully Interpreting Results, ISPOR 16th Annual European Congress, Dublin, Ireland, November 2-6, 2013, 2013 Poster, 2013 URL

Paulden, M and O'Mahony, JF, The 2013 Revision To NICE's Discounting Guidelines: Differential Discounting has Gone but Unjustified Selective Application Remains, ISPOR 16th Annual European Congress, Dublin, Ireland, November 2-6, 2013, 2013 Poster, 2013 URL

O'Mahony, JF, Critical Appraisal of Cost-Effectiveness Analyses of Human Papillomavirus Testing in Cervical Screening: Appropriate Comparisons and the Useful Interpretations of Results, 35th Annual North American Meeting of the Society for Medical Decision Making, Baltimore, MD, USA, October 19-23, 2013, 2013 Poster, 2013 URL

Ekwunife O, Gerber-Grote A, Mosch C, O'Mahony J, and Lhachimi S, Assessing cost-effectiveness of HPV vaccines with decision analytic models: what are the distinct challenges of low- and middle-income countries? A protocol for a systematic review, Systematic Reviews, 4, (68), 2015, p2 - 9 Journal Article, 2015 Other URL DOI

Paulden, M, O'Mahony, JF, Culyer, AJ, & McCabe, C, Objectivity and Equity: Clarity Required. A Response to Hill and Olson, PharmacoEconomics, 32, (12), 2014, p1249 - 1250 Journal Article, 2014 DOI Other URL

Paulden, M, O'Mahony, JF, Culyer, AJ, & McCabe, C, Some Inconsistencies in NICE's Consideration of Social Values, PharmacoEconomics, 32, (11), 2014, p1043 - 1053 Journal Article, 2014 URL Other DOI

Castanon A, Rebolj M, Burger EA, de Kok IMCM, Smith MA, Hanley SJB, Carozzi FM, Peacock S, O'Mahony JF., Cervical screening during the COVID-19 pandemic: optimising recovery strategies., The lancet. Public health, 6, (7), 2021, pe522-e527 Journal Article, 2021 DOI

Research Expertise


Dr O'Mahony's primary research interests are in methods of cost-effectiveness analysis (CEA), particularly modelling methods. Most broadly, James is interested in the way the policy questions faced by decision makers are interpreted by analysts when constructing models and communicating results back to decision makers. He is interested in how well the model estimates provided to decision makers fit the policy questions at hand. One of the areas of interest for James where models may not fit with policy questions is where there are multiple heterogeneous cohorts that are potential recipients of a given intervention. Cohort heterogeneity can arise for many reasons, including risk stratification or differential discounting, both of which have been subject of James's research. James is also interested in the methods used to determine and apply cost-effectiveness thresholds. His research has addressed the cost-effectiveness threshold in Ireland and to the extent it breached and fails to correspond with opportunity costs in the health system. Related to this, James is interested in the transparency of health systems regarding the resource allocation choices decision makers choose. Similarly, he is interested in appraisal frameworks that depart from the standard assumption that everyone's health is valued equally. James has an interest in technical aspects of cost-effectiveness analysis, including simulation methods. He enjoys working in R and operates a basic discrete event microsimulation for the purposes of methods demonstration.





Society of Medical Decision Making

International Society of Pharmacoeconomics and Outcomes Research

Health Economics Association of Ireland