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Hazard ratio funnel plots for survival comparisons
  1. P Silcocks
  1. Trent Cancer Registry, and the NIHR Research Design Service for the East Midlands, Nottingham, UK
  1. Correspondence to Dr P Silcocks, Medical Advisor, Trent Cancer Registry, 5 Old Fulwood Road, Sheffield, S10 3TG, UK; paul.silcocks{at}


Background: Funnel plots are a form of control chart that give a snapshot of many institutions at a particular moment in time. This paper describes how funnel plots may be constructed for survival analyses based on hazard ratios obtained from a Cox regression model with adjustment for covariates and allowance for overdispersion.

Method: Analysis of simulated and real survival data.

Results: It describes how centred hazard ratio estimates adjusted for covariates can be obtained from a Cox regression and gives details of the necessary programming in Stata. Allowance for overdispersion can be made by multiplying the standard errors by a factor based on either the model or the log-rank χ2 statistics. Simulated results and a real example are presented.

Conclusion: Funnel plots based on hazard ratios are easier to interpret than multiple Kaplan–Meier survival plots, and in contrast to funnel plots based on survival at, say, 5 years, are less open to accusations of bias and use more information. The interpretation of such plots may be enhanced by using standard meta-analysis methods. Hazard ratio comparisons may now be added to the repertoire of techniques used by Cancer Registries, Primary Care Trusts, and other commissioners of healthcare.

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  • All views expressed are personal and do not necessarily reflect Registry policy.

  • Competing interests None declared.

  • All views expressed are personal and do not necessarily reflect Registry policy.

  • Provenance and Peer review Not commissioned; externally peer reviewed.