Elsevier

Preventive Medicine

Volume 45, Issue 4, October 2007, Pages 247-251
Preventive Medicine

The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement: Guidelines for reporting observational studies,☆☆

https://doi.org/10.1016/j.ypmed.2007.08.012Get rights and content

Abstract

Much biomedical research is observational. The reporting of such research is often inadequate, which hampers the assessment of its strengths and weaknesses and of a study's generalisability. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Initiative developed recommendations on what should be included in an accurate and complete report of an observational study. We defined the scope of the recommendations to cover three main study designs: cohort, case–control and cross-sectional studies. We convened a 2-day workshop in September 2004, with methodologists, researchers, and journal editors to draft a checklist of items. This list was subsequently revised during several meetings of the coordinating group and in e-mail discussions with the larger group of STROBE contributors, taking into account empirical evidence and methodological considerations. The workshop and the subsequent iterative process of consultation and revision resulted in a checklist of 22 items (the STROBE Statement) that relate to the title, abstract, introduction, methods, results, and discussion sections of articles. 18 items are common to all three study designs and four are specific for cohort, case–control, or cross-sectional studies. A detailed Explanation and Elaboration document is published separately and is freely available on the websites of PLoS Medicine, Annals of Internal Medicine and Epidemiology. We hope that the STROBE Statement will contribute to improving the quality of reporting of observational studies.

Introduction

Many questions in medical research are investigated in observational studies (Glasziou et al., 2004). Much of the research into the cause of diseases relies on cohort, case–control, or cross-sectional studies. Observational studies also have a role in research into the benefits and harms of medical interventions (Black, 1996). Randomised trials cannot answer all important questions about a given intervention. For example, observational studies are more suitable to detect rare or late adverse effects of treatments, and are more likely to provide an indication of what is achieved in daily medical practice (Papanikolaou et al., 2006).

Research should be reported transparently so that readers can follow what was planned, what was done, what was found, and what conclusions were drawn. The credibility of research depends on a critical assessment by others of the strengths and weaknesses in study design, conduct, and analysis. Transparent reporting is also needed to judge whether and how results can be included in systematic reviews (Egger et al., 1998, Jüni et al., 2001). However, in published observational research important information is often missing or unclear. An analysis of epidemiological studies published in general medical and specialist journals found that the rationale behind the choice of potential confounding variables was often not reported (Pocock et al., 2004). Only few reports of case–control studies in psychiatry explained the methods used to identify cases and controls (Lee et al., 2007). In a survey of longitudinal studies in stroke research, 17 of 49 articles (35%) did not specify the eligibility criteria (Tooth et al., 2005). Others have argued that without sufficient clarity of reporting, the benefits of research might be achieved more slowly (Bogardus et al., 1999), and that there is a need for guidance in reporting observational studies (Anonymous, 1981, Rennie, 2001).

Recommendations on the reporting of research can improve reporting quality. The Consolidated Standards of Reporting Trials (CONSORT) Statement was developed in 1996 and revised 5 years later (Moher et al., 2001). Many medical journals supported this initiative (Moher et al., 2004), which has helped to improve the quality of reports of randomised trials (Egger et al., 2001, Plint et al., 2006). Similar initiatives have followed for other research areas—e.g., for the reporting of meta-analyses of randomised trials (Moher et al., 1999) or diagnostic studies (Bossuyt et al., 2003). We established a network of methodologists, researchers, and journal editors to develop recommendations for the reporting of observational research: the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement.

Section snippets

Aims and use of the STROBE Statement

The STROBE Statement is a checklist of items that should be addressed in articles reporting on the 3 main study designs of analytical epidemiology: cohort, case–control, and cross-sectional studies. The intention is solely to provide guidance on how to report observational research well: these recommendations are not prescriptions for designing or conducting studies. Also, while clarity of reporting is a prerequisite to evaluation, the checklist is not an instrument to evaluate the quality of

Development of the STROBE Statement

We established the STROBE Initiative in 2004, obtained funding for a workshop and set up a website (www.strobe-statement.org). We searched textbooks, bibliographic databases, reference lists, and personal files for relevant material, including previous recommendations, empirical studies of reporting and articles describing relevant methodological research. Because observational research makes use of many different study designs, we felt that the scope of STROBE had to be clearly defined early

STROBE components

The STROBE Statement is a checklist of 22 items that we consider essential for good reporting of observational studies (Table 1). These items relate to the article's title and abstract (item 1), the introduction (items 2 and 3), methods (items 4–12), results (items 13–17), and discussion sections (items 18–21) and other information (item 22 on funding). 18 items are common to all three designs, while four (items 6, 12, 14, and 15) are design-specific, with different versions for all or part of

Implications and limitations

The STROBE Statement was developed to assist authors when writing up analytical observational studies, to support editors and reviewers when considering such articles for publication, and to help readers when critically appraising published articles. We developed the checklist through an open process, taking into account the experience gained with previous initiatives, in particular CONSORT. We reviewed the relevant empirical evidence as well as methodological work, and subjected consecutive

Contributors

The following individuals have contributed to the content and elaboration of the STROBE Statement: Douglas G Altman, Maria Blettner, Paolo Boffetta, Hermann Brenner, Geneviève Chêne, Cyrus Cooper, George Davey-Smith, Erik von Elm, Matthias Egger, France Gagnon, Peter C Gøtzsche, Philip Greenland, Sander Greenland, Claire Infante-Rivard, John Ioannidis, Astrid James, Giselle Jones, Bruno Ledergerber, Julian Little, Margaret May, David Moher, Hooman Momen, Alfredo Morabia, Hal Morgenstern,

Acknowledgments

The workshop was funded by the European Science Foundation (ESF). Additional funding was received from the Medical Research Council Health Services Research Collaboration and the National Health Services Research & Development Programme. We are grateful to Gerd Antes, Kay Dickersin, Shah Ebrahim, and Richard Lilford for supporting the STROBE Initiative. We are grateful to the following institutions that have hosted working meetings of the coordinating group : Institute of Social and Preventive

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    In order to encourage dissemination of the STROBE Statement, this article is freely accessible on the Preventive Medicine website (http://www.elsevier.com/locate/ypmed), and will also be published in Annals of Internal Medicine, BMJ, Bulletin of the World Health Organization, Epidemiology, The Lancet, and PLoS Medicine. The authors jointly hold the copyright of this article. For details on further use, see STROBE website (http://www.strobe-statement.org).

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    Any exceptions to the normal Preventive Medicine article style are because of the simultaneous publication of this article in other journals.

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