Coming soon: CMAJ policy on data sharing
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* Diane Kelsall

In an editorial last year,1 we described *CMAJ*’s new policy on data sharing that will come into effect on July 1, 2018. After that date, authors of any research study submitted to the journal will need to supply a data-sharing statement, and those using shared data will need to acknowledge the source of the data. Additionally, all reports of clinical trials submitted to *CMAJ* that begin enrolling participants on or after Jan. 1, 2019, must include a data-sharing statement in the registration of the trial. Changes to the data-sharing plan after registration should be updated in the registry record and clearly described in the statement submitted to *CMAJ*.

Sharing data is a natural extension of the collaboration that is common in the scientific community. It respects the contribution of study participants and allows for the advancement of science, particularly in transparency and reproducibility of studies. Sharing data allows for further insights to be gleaned from data sets that can be used for the public good, especially given that tax dollars fund much research.

*CMAJ’*s new policy on data sharing brings the journal in line with the latest recommendations from the International Committee of Medical Journal Editors (ICMJE).2 Indeed, *CMAJ* has had a policy requiring data-sharing statements for reports of clinical trials of drugs and medical devices since 2014.3 In an effort to promote transparency of the research record and reduce research waste, we will be extending that policy to all types of research studies in July.

To be clear, we are not requiring authors to share their data, although that would be ideal. Instead, we are asking authors to provide specific details on the availability of their data sets for use by other researchers. As per the ICMJE recommendations, we will be requiring authors to supply the following information in their data-sharing statement: which data will be shared; whether individual anonymized participant data will be shared; whether associated documents, such as the statistical analysis plan or study protocol, will be available; when the data will become available and for how long; and the specific requirements for accessing the data (e.g., who is eligible, for what types of analyses, and how the data will be made available).2 Examples of data-sharing statements that fulfill ICMJE requirements are available at icmje.org.4

Just as research teams develop plans for statistical analysis or dissemination, they will also need to consider thoughtfully how best to share their data on study completion, including maintaining the privacy of participants, and the integrity and quality of the data. Research ethics boards will need to consider these factors when granting approval. Although some research groups have expressed reluctance to share data for a variety of reasons, a decision to withhold data should not be made lightly.

Accountability for data sharing does not lie only with those who share their data, however. Researchers who use shared data for secondary analyses also have responsibilities when publishing their work. Ideally, researchers who would like to use another group’s data sets and those who generated that data should collaborate. This may not always be possible. However, the work of researchers sharing their data needs to be clearly acknowledged, 4 given the substantial financial, time and other resource commitments necessary to conduct research that contributes meaningfully to the scientific record, and is methodologically and ethically sound.

To that end, the following information will be required in submissions from those using shared data: an attestation that the use of the data was in accordance with any agreed-upon terms, and explicit identification of the source of the data with a persistent identifier. Authors should also explain how their analysis differs from previous analyses.4 Including this information will help ensure that credit is given where credit is due, facilitate searches for related studies and contribute to reducing unnecessary study duplication.

It has been 14 years since ICMJE first published its policy requiring the registration of clinical trials.5 Since then, thought among the academic community about the ethical conduct of research has evolved considerably. As ICMJE stated in 2004, “Registration is only part of the means to an end.”5 Requiring data-sharing statements is another step toward a future where data sets are shared and reused — respecting the contributions of researchers and participants alike — to improve the health of all.

## Footnotes

*   **Competing interests:** See [www.cmaj.ca/site/misc/cmaj\_staff.xhtml](http://www.cmaj.ca/site/misc/cmaj_staff.xhtml)

## References

1.  Kelsall D. New *CMAJ* policy on sharing study data. CMAJ 2017;189:E1082.
    
    [FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiRlVMTCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czoxMjoiMTg5LzM0L0UxMDgyIjtzOjQ6ImF0b20iO3M6MjI6Ii9jbWFqLzE5MC8yMS9FNjM1LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

2.  Taichman DB, Sahni P, Pinborg A, et al. Data sharing statements for clinical trials: a requirement of the International Committee of Medical Journal Editors. Ann Intern Med 2017;167:63–5.
    
    

3.  Fletcher J. New *CMAJ* policy on sharing data from clinical research. CMAJ 2014; 186:163.
    
    [FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiRlVMTCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czo5OiIxODYvMy8xNjMiO3M6NDoiYXRvbSI7czoyMjoiL2NtYWovMTkwLzIxL0U2MzUuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

4.  Clinical trials. International Committee of Medical Journal Editors; 2018. Available: [www.icmje.org/recommendations/browse/publishing-and-editorial-issues/clinical-trial-registration.html#two](http://www.icmje.org/recommendations/browse/publishing-and-editorial-issues/clinical-trial-registration.html#two) (accessed 2018 Apr. 19).
    
    

5.  De Angelis C, Drazen JM, Frizelle FA, et al. Clinical trial registration: a statement from the International Committee of Medical Journal Editors. CMAJ 2004;171:606–7.
    
    [FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiRlVMTCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czo5OiIxNzEvNi82MDYiO3M6NDoiYXRvbSI7czoyMjoiL2NtYWovMTkwLzIxL0U2MzUuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9)