Table 3 Classification system for DSS (version 2)

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Unclear

DSS not understood. Either the statement makes no sense (e.g., is not coherent English), or IPD is not mentioned at all, or IPD is mentioned but the intention to share or not share is not made clear, even in the vaguely positive sense described by ‘vaguely positive’ below.

N.B. Responses that indicate that ‘demographic data’ or ‘clinical data’ or similar will be shared are ambiguous – the data could be summary tables rather than IPD. Unless clarified elsewhere in the DSS, therefore, such responses fall into this category. In all cases the intention, or not, to share IPD for secondary use is simply unknown.

N

No sharing

DSS states or implies that there will be no sharing of IPD. Different specific reasons may be provided. Usually an explicit statement is made (e.g. “transfer of data to third parties excluded”) but sometimes a reference is made to an implied reason for not sharing (“patients’ confidentiality”). DSS that refer only to sharing of aggregate or results data, or only to publication of a journal paper are also assumed to fall into the ‘no sharing’ category.

0

No plans

DSS states that there are currently no plans regarding IPD sharing, or a decision has not yet been made. Usually, an explicit statement but may be implicit in statements such “need to consult with collaborators / participants”. N.B. “Not yet planned…” would fall into this category, while “not planned…” would be classified as ‘no sharing’.

V

Vaguely positive

Vaguely positive. DSS states or implies that there will be some degree of IPD sharing, but no details are given or sharing appears limited, e.g. “To be made available at a later date”. This is the weakest of the positive statements. Sometimes the intention is made clear but the details are not yet available – e.g. “The investigators will be sharing the data, but the management plan is being designed.”

R

By request

DSS states that IPD can be obtained by request, usually as an explicit statement, occasionally just as an email address. Few further details about the access process are provided and there are no additional prerequisites identified (other than, sometimes, the fact that a Data Use Agreement must be signed). The contact person is usually the investigator, sometimes the sponsor, but the role may not be stated.

C

Complex

DSS states or implies that IPD will be available and describes or references a more complex regime than a simple request. Common additional requirements are for requests to be reviewed by a data access or trial committee, for the applicants to have an approved protocol, or to follow a named procedure set out in a document or web page. These DSS are therefore positive but provide more detail than simply stating the data can be requested.

S

Via Storage

DSS explicitly states that IPD will be transferred to a specific data repository – may be general, specific to clinical research or institutional - which would normally be named. The data repository (e.g., CSDR, Vivli, or Yoda) should have its own access policies and procedures, and not be just a repository for publicly available documents (e.g., Zenodo). This is a version of the ‘complex+’ category above, but with the additional requirements partially provided by repository systems.