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About Sickkids
About SickKids

Andrew Willan, PhD

Research Institute
Senior Scientist Emeritus
Child Health Evaluative Sciences

University of Toronto
Professor of Biostatistics
Dalla Lana School of Public Health

Phone: 416-813-2166
Fax: 416-813-5979
Email: andy@andywillan.com

For more information, visit:

http://www.andywillan.com »»

Research Interests

  • Biostatistics
  • Clinical trial methodology
  • Health economics
  • Diagnostic tests

Research Activities

  1. Development of biostatistical methods in clinical trial methodology, health economics and cost-effectiveness analysis.
  2. Clinical trials in Paediatrics and Obstetrics.


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. Accounting for between-study variation in incremental net benefit in value of information methodology. Health Economics 2012; 21(10):1183–1195.

Willan AR, Eckermann S. Value of information and pricing new health care interventions. PharmacoEconomics 2012; 30(6):447-459.

Pullenayegum EM, Willan AR. Marginal models for censored longitudinal cost data: appropriate working variance matrices in inverse-probability-weighted GEEs can improve precision. International Journal of Biostatistics 2011; 7(1); www.bepress.com/ijb/vol7/iss1/14.

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):1-10.

Willan AR, Eckermann S. Optimal clinical trial design using value of information methods with imperfect implementation. Health Economics 2010; 19:549-561.

Eckermann S, Coory M, Willan AR. Indirect comparison: relative risk fallacies and odds solution. Journal of Clinical Epidemiology 2009; 62:1031-1036.

Eckermann S, Willan AR. Globally optimal trial design for local decision making. Health Economics 2009; 18:203-216.

Hossain A, Beyene J, Willan AR, Hu P. Approximate Likelihood ratio test for detecting differential expression in microarray data. Computational Statistics and Data Analysis 2009; 53(10):3685-3695.

Hodnett ED, Stremler R, Willan AR, Weston JA, Lowe NK, Simpson KR, Fraser WD, Gafni A; SELAN (Structured Early Labour Assessment and Care by Nurses) Trial Group, et al. Effect on birth outcomes of a formalised approach to care in hospital labour assessment units: international, randomised controlled trial. BMJ 2008; 337:a1021.

Murphy KE, Hannah ME, Willan AR et al. Multiple courses of antenatal corticosteroids for preterm birth study (MACS): a randomised controlled trial. Lancet 2008; 372:2143-2151

Willan AR. Optimal sample size determinations from an industry perspective based on the expected value of information. Clinical Trials 2008; 5:587-594.

Eckermann S, Willan AR. The option value of delay in health technology assessment. Medical Decision Making, 2008; 28:300-305.

Eckermann S, Briggs A, Willan AR. Health technology assessment in the cost-disutility plane. Medical Decision Making 2008; 28:172-181.

Eckermann S, Willan AR. Time and EVSI wait for no patient. Value in Health 2008; 11:522-526.

Willan AR, Kowgier ME. Determining optimal sample sizes for multi-stage randomized clinical trials using value of information methods. Clinical Trials 2008; 5:289-300.

Willan AR, Kowgier ME. Cost-effectiveness analysis of a multinational RCT with a binary measure of effectiveness and an interacting covariate. Health Economics 2008; 17:777-791.

Willan AR. Clinical decision making and the expected value of information. Clinical Trials 2007; 4:279-285.

Hossain A, Willan AR. Approximate MLEs of the parameters of location-scale models under type II censoring. Statistics 2007; 41(5): 385-394.

Pullenayegum EM, Willan AR. Semi-parametric regression models for cost-effectiveness analysis: improving the efficiency of estimation from censored data. Statistics in Medicine 2007; 26:3274-3299.

Eckermann S, Willan AR. Expected value of information and decision making in HTA. Health Economics. 2007; 16:195-209.

Manca A, Willan AR. Lost in translation: accounting for between country differences in the analysis of multinational cost effectiveness data. Pharmacoeconomics 2006; 24:1101-1119.

Willan AR, Briggs AH. The statistical analysis of cost-effectiveness data. Chichester UK: Wiley, 2006.

Willan AR. Statistical analysis of cost-effectiveness data from randomized clinical trials. Expert Rev. Phamacoeconomics Outcomes Res. 2006; 6:337-346.

Willan AR, Goeree, R, Pinto EM, McBurney C, Blackhouse G. Economic evaluation of rivastigmine in patients with Parkinson’s disease dementia. Pharmacoeconomics. 2006; 24:93-106.

Pinto EM, Willan AR and O’Brien BJ. Cost-effectiveness analysis for multinational clinical trials Statistics in Medicine. 2006; 24:1965-82.

Willan AR, Pinto EM. The expected value of information and optimal clinical trial design. Statistics in Medicine; 2005; 24:1791-1806.

Willan AR, Pinto EM, O’Brien BJ, Kaul P, Goeree R, Lynd L, Armstrong PW. Country specific cost comparisons from multinational clinical trials using empirical Bayesian shrinkage estimation: the Canadian ASSENT-3 economic analysis. Health Economics; 2005; 14: 327-338.

Willan AR, Lin DY, Manca A. Regression methods for cost-effectiveness analysis with censored data. Statistics in Medicine; 2005; 24:131-145.

Willan AR. Incremental net benefit in the analysis of economic data from clinical trials with application to the CADET-Hp Trial. European Journal of Gastroenterology and Hepatology; 2004; 16:543-549.

Willan AR, Briggs AH, Hoch JS. Regression methods for covariate adjustment and subgroup analysis for non-censored cost-effectiveness data. Health Economics; 2004; 13: 461-475.

Sears MR, Greene JM, Willan AR, Wiecek, EM, Taylor DR, Flannery EM, Cowan JO, Herbison GP, Silva PA, Poulton R. Persistence, remission and relapse of childhood asthma followed to adulthood: a longitudinal population-based cohort study. NEJM; 2003; 349(15): 1414-1422.

Willan AR, Chen E, Cook RJ, Lin DY. Incremental net benefit in randomized clinical trials with qualify-adjusted survival. Statistics in Medicine; 2003; 22:353-362.

Willan AR, Lin DY, Cook RJ, Chen E. Using inverse-weighing in cost-effectiveness analysis with censored data. Statistical Methods in Medical Research; 2002; 11:539-552.

Sears MR, Greene JM, Willan AR, Taylor DR, Flannery EM, Herbison GP, Poulton R. The long-term relationship between breast-feeding and development of atopy and asthma in children and young adults: a longitudinal study. The Lancet, 2002; 360;901-907.

O'Brien BJ, Gertsen K, Willan AR, Faulkner L. Is there a kink in consumers' threshold value for cost-effectiveness in health care. Health Economics. 2002; 11:175-180.

Willan AR, Lin DY. Incremental net benefit in randomized clinical trials. Stat Med. 2001; 20:1563-1574.

Willan AR. Analysis, sample size and power for estimating incremental net health benefit from clinical trial data. Control Clin Trials. 2001; 22:228-237.

Willan AR, O'Brien BJ, Leyva RA. Cost-effectiveness analysis when the WTA is greater than the WTP. Stat Med, 2001; 20:3251-3259.

Hoch JS, Briggs AH, Willan AR. Something old, something new, something borrowed, something blue: a framework for the marriage of health econometrics and cost-effectiveness analysis. Health Economics, 2001; 11:415-430.

Willan AR, O'Brien BJ. Cost prediction models for the comparison of two groups. Health Econ Let, 2001; 5:20-25.<</p>

Willan AR. On the probability of cost-effectiveness using data from randomized clinical trials. BMC Med Res Meth, 2001; 1:8. ( www.biomedcentral.com/1471-2288/1/8/ )

Hannah ME, Hannah, WJ, Hewson SA, Hodnett ED, Saigal S, Willan AR. Term Breech Trial: a multicentre international randomised controlled trial of planned caesarean section and planned vaginal birth for breech presentation at term. The Lancet, 2000; 356:1375-1383.

Willan AR, O'Brien BJ. Sample size and power issues in estimating incremental cost-effectiveness ratios from clinical trials data. Health Economics 1999; 8:203-211.