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Faculty Member

Andrew Willan PhD-Biostatistics, MSc-Statistics, BEd-Math and PHE, BA-Economics and Math

Email Address(es)
Office Phone
Office Address
Program in Child Health Evaluative Sciences/SickKids Research Institute 686 Bay Street, Room 11.9708 Toronto, ON M5G 1E2
Andy Willan's Home Page, Internet Randomization Service
Curriculum Vitae
Biostatistics Division
SGS Status
Full Member
Appointment Status
Status Only
Currently Accepting Doctoral Students?

Research Interests

  • Clinical trials methodology
  • Statistical analysis of cost-effectiveness data
  • Expected value of information and optimal design of clinical trials
  • Bayesian analysis of randomised clinical trials

Education & Training History

  • PhD in Biostatistics from the Department of Epidemiology and Biostatistics at the University of Western Ontario, London ON, 1979.
  • MSc in Statistics from Queen’s University, Kingston ON, 1976.
  • BEd in Mathematics and Physical Education from Queen’s University, Kingston ON, 1972.
  • BA in Economics and Mathematics from York University, Toronto ON, 1970.

Other Affiliations

Senior Scientist Emeritus, Program in Child Health Evaluative Sciences, SickKids Research Institute

Professor Emeritus, Department of Clinical Epidemiology and Biostatistics, McMaster University

Primary Teaching Responsibilities

  • Advanced Statistical Methods for Clinical Trials (CHL 5225 H)

Honours & Awards

  • TBA

Current Research Projects

  • CIHR. Impact of Emergency Department Probiotic Treatment of Pediatric Gastroenteritis: Randomized Controlled Trial. Stephen Freedman (Principal Investigator), Willan AR, and 9 others. $2,231,300, 2013-2018.
  • CIHR. Sucrose Practices for Pain in Neonates (SPiN); A Program of Research. Bonnie Stevens (Principal Investigator), Willan AR, and 12 others. $1,246,500, 2013-2018.
  • IMPACT. Comparing the complex care for kids Ontario (CCKO) province-wide integrated care intervention for children with medical complexity (CMC) to waitlist controls using a patient-engaged evaluation framework and mixed method design. Nora Fayed (Principal Investigator), Willan AR, and 16 others. $300,000, 2016-2018.
  • IMPACT. Addressing obesity in toddlers at risk: a pragmatic randomized controlled trial comparing usual care to group-based parenting and home visits in primary care. Catherine Birken (Principal Investigator), Willan AR, and 11 others. $299,723, 2016-2018.
  • CIHR – Foundation Scheme – 2nd Live Pilot. Effective Knowledge Translation Strategies for Enhancing Impact and Improving Outcomes in Infant Pain. Bonnie Stevens (Principal Investigator), Willan AR, and 13 others. $3,823,346. 2016-2023.
  • CIHR – Project Scheme – 1st Live Pilot. Evaluating the effectiveness of an online knowledge translation intervention for minimizing procedural pain in hospitalized infants. Bonnie Stevens (Principal Investigator), Willan AR, and 13 others. ($1,116,171). Declined. 2016-2021.
  • CIHR – Project Scheme. Intermittent vs. Continuous Oxygen Saturation Monitoring in Infants Hospitalized for Bronchiolitis: A Randomized Controlled Trial. Sanjay Mahant (Principal Investigator), Willan AR, and 9 others. ($1,823,340). 2016-2020.
  • CIHR – Foundation Scheme – 2nd Live Pilot. Necrotizing Entero Colitis (NEC) Research Program: introducing innovative therapies to halt the disease progression and promote recovery. Agostino Pierro (Principal Investigator), Willan AR, and others. $. 2016-2023.
  • CIHR – Innovative Clinical Trials. Four trials with Pediatric Emergency Research Canada. Klassen TP. (Principal Investigator), Willan AR, and 26 others. ($3,000,000). 2017-20.

Representative Publications

  • Willan AR, Thabane L. Bayesian methods for Pilot Studies. Clinical Trials. Published online 2020 April 16.
  • Roth DE, Morris SK, Zlotkin S, Willan AR, et al. Vitamin D supplementation in pregnancy and lactation and infant growth. New England Journal of Medicine 2018; 379(6):535-546.
  • Freedman SB, Williamson-Urquhart S, Farion KJ, Gouin S, Willan AR et al. Multicenter trial of a combination probiotic for children with gastroenteritis. New England Journal of Medicine 2018; 379(21):2015-2026.
  • Willan AR. Accounting for treatment by center interaction in sample size determinations and the use of surrogate outcomes in the pessary for the prevention of preterm birth trial: a simulation study. BMC Trials 2016 17(1):310.
  • Chan KKW, Xie F, Willan AR. Gupta M, Pullenayegum E. Underestimation of variance of predicted health utilities derived from multi-attribute utility instruments: the use of multiple imputation as a possible solution. Medical Decision Making 2016; DOI 1011.77/0272989X16650181.
  • Chen MH, Willan AR. Value of information methods for assessing a new diagnostic test. Statistics in Medicine 2014; 33(11):1801-1815.
  • Chan KKW, Willan AR, Gupta M, Pullenayegum E. Underestimation of Uncertainties in Health Utilities derived from Mapping Algorithms involving Health Related Quality of Life Measures: Statistical Explanations and Potential Remedies. Medical Decision Making 2014; 34(7):863-872.
  • Willan AR. Bayesian decision theory and the design and analysis of randomized clinical trials. In: Development in Statistical Evaluation of Clinical Trials. K. van Montfort, J. Oud und W. Ghidey (ed). Springer-Verlag 2014.
  • Willan AR. Bayesian methods provide important advantages for the design, analysis and interpretation of clinical studies. In: Important Considerations for Clinical Trial Methodologies. Future Medicine 2013. doi: 10.4155/9781909453319.
  • Chen MH, Willan AR. Determining optimal sample sizes for multistage adaptive randomized clinical trials from an industry perspective using value of information methods. Clinical Trials 2013; 10(1):54–62.
  • Eckermann S, Willan AR. Optimal global VOI trials: better aligning manufacturer and decision maker interests and enabling feasible risk sharing. PharmacoEconomics 2013; 31(5):393-401.
  • Hossain A, Willan AR, Beyene J. A flexible nonparametric approach to find candidate genes associated to disease in microarray experiments. Journal of Bioinformatics and Computational Biology 2013; 11(2):1250021 (19 pages).
  • Hossain A, Willan AR, Beyene J. An improved method on Wilcoxon rank sum test for gene selection from microarray experiments. Communications in Statistics 2013; 42(7):1563-1577.
  • Willan AR, Goeree R, Boutis K. Value of Information methods for planning and analyzing clinical studies optimize decision making and research planning. Journal of Clinical Epidemiology 2012; 65(8):870-876.
  • Willan AR, Eckermann S. Value of information and pricing new health care interventions. PharmacoEconomics 2012; 30(6):447-459.
  • Willan AR, Eckermann S. Accounting for between-study variation in incremental net benefit in value of information methodology. Health Economics 2012; 21(10):1183–1195.
  • Pullenayegum EM, Willan AR. Marginal models for censored longitudinal cost data: appropriate working variance matrices in inverse-probability-weighted GEEs can improve precision. The International Journal of Biostatistics 2011; 7(1), Article 14.
  • Willan AR. Sample size determination for cost-effectiveness trials. PharmacoEconomics 2011; 29(11):933-949.
  • Eckermann S, Willan AR. Presenting and summarizing cost and effect evidence to best inform inference and societal decision making when comparing multiple strategies. PharmacoEconomics 2011; 29(7):563-577.
  • Eckermann S, Coory M, Willan AR. Consistently estimating risk difference when translating evidence to jurisdiction of interest. PharmacoEconomics 2011; 29(2):87-96.
  • Eckermann S, Karnon J, Willan AR. The value of information: Best informing research design and prioritization using current methods. PharmacoEconomics 2010; 28(9):699-709.
  • Willan AR, Eckermann S. Optimal clinical trial design using value of information methods with imperfect implementation. Health Economics 2010; 19:549-561.
  • Hossain A, Beyene J, Willan AR, Hu P. A flexible approximate likelihood ratio test for detecting differential expression in microarray data. Computational Statistics and Data Analysis 2009; 53(10):3685-3695.
  • Eckermann S, Coory M, Willan AR. Indirect comparison: relative risk fallacies and odds solution. Journal of Clinical Epidemiology 2009; 62(10): 1031-1036.
  • Eckermann S, Willan AR. Globally optimal trial design for local decision making. Health Economics 2009; 18(2): 203-216.
  • Willan AR. Optimal sample size determinations from an industry perspective based on the expected value of information. Clinical Trials 2008; 5(6): 587-594.
  • Willan AR, Kowgier ME. Determining optimal sample sizes for multi-stage randomized clinical trials using value of information methods. Clinical Trials 2008; 5(4): 289-300.