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Translation of Oxford’s CEBM catalogue of bias into Portuguese: contributing to the dissemination of conscientious thinking on health research
  1. Rafael Leite Pacheco1,2,
  2. Carolina de Oliveira Cruz Latorraca1,
  3. Ana Luiza Cabrera Martimbianco2,3,
  4. Luis Eduardo Santos Fontes4,5,
  5. Regis Vieira1,6,
  6. Enderson Miranda5,
  7. David Nunan7,
  8. Rachel Riera8,9
  1. 1 Evidence-Based Healthcare Postgraduate Program, Universidade Federal de São Paulo (Unifesp), São Paulo, Brazil
  2. 2 Research Center for Medical School, Centro Universitário São Camilo, São Paulo, Brazil
  3. 3 Health and Environment Postgraduate Program, Universidade Metropolitana de Santos, Santos, Brazil
  4. 4 Evidence-Based Healthcare Research Group, Faculdade de Medicina de Petrópolis, Petrópolis, Brazil
  5. 5 Centre for Evidence-Based Medicine (CEBM), University of Oxford, Oxford, UK
  6. 6 Family and Community Medicine Department, Hospital Albert Einstein, São Paulo, Brazil
  7. 7 Primary Care Health Sciences, University of Oxford, Oxford, UK
  8. 8 Evidence-Based Medicine Discipline, Universidade Federal de São Paulo (Unifesp), São Paulo, Brazil
  9. 9 Centre of Health Technology Assessment, Hospital Sírio-Libanês, São Paulo, Brazil
  1. Correspondence to Luis Eduardo Santos Fontes, Evidence-Based Healthcare Research Group, Faculdade de Medicina de Petrópolis, Petrópolis 25680120, Brazil; luis.fontes{at}

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The catalogue of bias

Biases may arise in any stage of healthcare research and are likely to influence the magnitude and direction of the results.1 Understanding where and how different biases emerge in the research process allows researchers to properly design studies that can prevent or counteract the impact of biases. Furthermore, to assess the risk of bias within published studies is imperative when drafting any research synthesis and clinical practical guidelines.

Sackett, in a remarkable paper published in 1979, ‘Bias in Analytic Research’, was the first to propose a catalogue that would include a list of biases that ‘may distort the design, execution, analysis and interpretation of research’.1 2 Sacket’s pioneering work identified, labelled and discussed 35 biases. In the conclusion of this paper, Sackett highlighted, among others, two priorities for future researches: the continued development of the proposed catalogue and the empirical evaluation of the proposed biases.2

Forty years after Sackett’s paper, a group of researchers from the University of Oxford’s Centre for Evidence-Based Medicine (CEBM) decided to continue Sackett’s mission by creating an expansion to his original catalogue of bias.1 Fifty-two biases have been catalogued and discussed so far. All the content related to each bias is freely available at the official catalogue’s website (, including any new biases that may be catalogued after the publication of this article.

Although Sackett had little empirical evidence on the proposed original biases, the development of systematic methodologies for identifying biases and …

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  • Contributors Conception and design: RR, LESF, EM and DN. Data acquisition: all authors. Drafting the work: RLP, CdOCL and ALCM. Revising content: RR and DN. Final approval: all authors.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

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

  • Data availability statement There are no data in this work.