. 2016 Nov 24;17:557. doi: 10.1186/s13063-016-1686-5

Table 1.

Elements in the proposed metadata scheme for clinical research data objects

Mandatory	Recommended	Optional
A.1 Source study title^a	A.2 Study identifier records^a A.3 Study topics^a
B.1 DOI (1) B.3 Object title	B.5 Version	B.2 Object other identifiers^a B.4 Object additional titles^a
C.1 Creators^a		C.2 Contributors^a
D.1 Creation year		D.2 Dates^a
E.1 Resource type general	E.2 Resource type E.3 Description^a E.5 Language E.6 Related identifiers^a	E.4 Subjects (of data object)^a
F.1 Publisher F.3 Access type F.4 Access details (2) F.5 Access contact (2) F.6 Resources^a	F.2 Other hosting institutions^a	F.7 Rights^a

DOI Digital object identifier

(1) Mandatory for publicly accessible data objects, recommended for all others

(2) Mandatory if access is non-public

^aMay be repeating