Two researchers in lab coats working in a laboratory each looking through a microscope.

Many journals require researchers to state whether they will share the data that underlie papers.Credit: Getty

Most biomedical and health researchers who declare their willingness to share the data behind journal articles do not respond to access requests or hand over the data when asked, a study reports1.

Livia Puljak, who studies evidence-based medicine at the Catholic University of Croatia in Zagreb, and her colleagues analysed 3,556 biomedical and health science articles published in a month by 282 BMC journals. (BMC is part of Springer Nature, the publisher of Nature; Nature’s news team is editorially independent of its publisher.)

The team identified 381 articles with links to data stored in online repositories and another 1,792 papers for which the authors indicated in statements that their data sets would be available on reasonable request. The remaining studies stated that their data were in the published manuscript and its supplements, or generated no data, so sharing did not apply.

But of the 1,792 manuscripts for which the authors stated they were willing to share their data, more than 90% of corresponding authors either declined or did not respond to requests for raw data (see ‘Data-sharing behaviour’). Only 14%, or 254, of the contacted authors responded to e-mail requests for data, and a mere 6.7%, or 120 authors, actually handed over the data in a usable format. The study was published in the Journal of Clinical Epidemiology on 29 May.

DATA-SHARING BEHAVIOUR. Graphic showing percentage of authors that were willing to share data.

Source: Livia Puljak et al

Puljak was “flabbergasted” that so few researchers actually shared their data. “There is a gap between what people say and what people do,” she says. “Only when we ask for the data can we see their attitude towards data sharing.”

“It’s quite dismaying that [researchers] are not coming forward with the data,” says Rebecca Li, who is executive director of non-profit global data-sharing platform Vivli and is based in Cambridge, Massachusetts.

Data-availability statements are of little value because many of the data sets are never actually made accessible, says Valentin Danchev, a sociologist at the University of Essex in Colchester.

Puljak’s results square with those of a study that Danchev led, which found low rates of data sharing by authors of papers in leading medical journals that stipulate all clinical trials must share data2.

Persistent barriers

Researchers who declined to supply data in Puljak’s study gave varied reasons. Some had not received informed consent or ethics approval to share data; others had moved on from the project, had misplaced data or cited language hurdles when it came to translating qualitative data from interviews.

Aidan Tan, a paediatric physician and researcher in evidence-based medicine at the University of Sydney in Australia, says the study demonstrates that persistent barriers stop researchers sharing their data. His own research surveying leaders of clinical trials has found concerns about data privacy, participant confidentiality and data being misused in misleading secondary analyses3. Investigators might also want to publish more original research first, or fear getting scooped.

Past research suggests that some fields, such as ecology, embrace data sharing more than others. But multiple analyses of COVID-19 clinical trials — including some from Li4,5 and Tan6 — have reported that anywhere from around half to 80% of investigators are unwilling or not planning to share data freely.

“It is concerning,” Tan says, “that data-sharing practices do not appear to have improved at all during the COVID-19 pandemic, despite high-profile calls for data sharing” from funding organizations such as Wellcome in London, the US National Institutes of Health and the World Health Organization.

Tackling the problem

Li surmises that many researchers don’t fully understand what data sharing actually entails: that data underpinning manuscripts “should be ready, formatted and available for whoever asks”, she says.

To encourage researchers to prepare their data, Li says, journals could make data-sharing statements more prescriptive. They could require authors to detail where they will share raw data, who will be able to access it, when and how.

Funders could also raise the bar for data sharing. The US National Institutes of Health, in an effort to curb wasteful, irreproducible research, will soon mandate that grant applicants include a data-management and sharing plan in their applications. Eventually, they will be required to share data publicly.

“The power to move data sharing forward rests with those that have currency with researchers to change the culture,” Li says.