SAS and R code for probabilistic quantitative bias analysis for misclassified binary variables and binary unmeasured confounders

Matthew P. Fox, Richard F. Maclehose, Timothy L. Lash

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Systematic error from selection bias, uncontrolled confounding, and misclassification is ubiquitous in epidemiologic research but is rarely quantified using quantitative bias analysis (QBA). This gap may in part be due to the lack of readily modifiable software to implement these methods. Our objective is to provide computing code that can be tailored to an analyst's dataset. We briefly describe the methods for implementing QBA for misclassification and uncontrolled confounding and present the reader with example code for how such bias analyses, using both summary-level data and individual record-level data, can be implemented in both SAS and R. Our examples show how adjustment for uncontrolled confounding and misclassification can be implemented. Resulting bias-Adjusted point estimates can then be compared to conventional results to see the impact of this bias in terms of its direction and magnitude. Further, we show how 95% simulation intervals can be generated that can be compared to conventional 95% confidence intervals to see the impact of the bias on uncertainty. Having easy to implement code that users can apply to their own datasets will hopefully help spur more frequent use of these methods and prevent poor inferences drawn from studies that do not quantify the impact of systematic error on their results.

Original languageEnglish (US)
Pages (from-to)1624-1633
Number of pages10
JournalInternational journal of epidemiology
Issue number5
StatePublished - Oct 1 2023

Bibliographical note

Publisher Copyright:
© 2023 The Author(s) 2023; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.


  • Bias analysis
  • bias
  • epidemiologic methods
  • systematic error

PubMed: MeSH publication types

  • Journal Article
  • Research Support, N.I.H., Extramural


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