Willem H Collier

Assistant Professor Of Clinical Population and Public Health Sciences

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I am an Assistant Professor of Clinical Population and Public Health Sciences in the Division of Biostatistics of the Department of Population and Public Health Sciences at the University of California. Before joining USC, I completed undergraduate degrees in mathematics and economics and a PhD in Population Health Sciences with an emphasis in Biostatistics at the University of Utah. I support the design, conduct, and analysis of pediatric cancer clinical trials of the Children’s Oncology Group, where I focus on cancer control, late effects, and cellular therapy trials. I also work on statistical methods for the evaluation of surrogate endpoints and collaborate with the Chronic Kidney DIsease Epidemiology Collaboration for my work in this area.


  • Comparing Bayesian hierarchical meta-regression methods and evaluating the influence of priors for evaluations of surrogate endpoints on heterogeneous collections of clinical trials BMC Med Res Methodol. 2024 Feb 16; 24(1):39. . View in PubMed
  • A meta-analysis of GFR slope as a surrogate endpoint for kidney failure Nat Med. 2023 07; 29(7):1867-1876. . View in PubMed
  • Change in Albuminuria and GFR Slope as Joint Surrogate End Points for Kidney Failure: Implications for Phase 2 Clinical Trials in CKD J Am Soc Nephrol. 2023 06 01; 34(6):955-968. . View in PubMed
  • Evaluation of Variation in the Performance of GFR Slope as a Surrogate End Point for Kidney Failure in Clinical Trials that Differ by Severity of CKD Clin J Am Soc Nephrol. 2023 02 01; 18(2):183-192. . View in PubMed
  • Handling missing within-study correlations in the evaluation of surrogate endpoints Stat Med. 2023 11 20; 42(26):4738-4762. . View in PubMed
  • Characteristics of Nonelderly Adult Health Care Persistent Super Utilizers in Utah Popul Health Manag. 2022 08; 25(4):472-479. . View in PubMed
  • Patient-reported opioid use for tissue expander-based breast reconstruction J Plast Reconstr Aesthet Surg. 2021 Nov; 74(11):2899-2905. . View in PubMed
  • A Nationwide Analysis of Early and Late Readmissions following Free Tissue Transfer for Breast Reconstruction J Reconstr Microsurg. 2020 Jul; 36(6):450-457. . View in PubMed
  • A Comparison of Common Plastic Surgery Operations Using the NSQIP and TOPS Databases Plast Reconstr Surg Glob Open. 2020 May; 8(5):e2841. . View in PubMed
  • The Rate of Infectious Complications After Intrathecal Drug Delivery System Implant for Cancer-Related Pain Is Low Despite Frequent Concurrent Anticancer Treatment or Leukopenia Anesth Analg. 2020 07; 131(1):280-287. . View in PubMed
  • 2011 ACGME Duty Hour Limits had No Association With Breast Reconstruction Complications J Surg Res. 2020 03; 247:469-478. . View in PubMed
  • Examining the relationship between epidural steroid injections and patient satisfaction Spine J. 2020 02; 20(2):207-212. . View in PubMed
  • Direct Comparison of Patient-completed and Physician-completed Caprini Scores for Plastic Surgery Patients Plast Reconstr Surg Glob Open. 2019 Aug; 7(8):e2363. . View in PubMed
  • Plast Reconstr Surg. 2019 09; 144(3):360e-368e. . View in PubMed
  • A national analysis of readmissions for wound healing complications following the repair of lower back, hip, and buttock pressure ulcers using the Nationwide Readmissions Database Am J Surg. 2019 04; 217(4):658-663. . View in PubMed