munging metadata

What’s in a Value Level Metadata (VLM) Library? SHARE has the capability to store and publish Value Level Metadata (VLM) content. Currently, the only CDISC standard describing VLM is Define-XML. Define-XML provides the structure for VLM along with some guidelines on when it’s useful, but it does not provide standard VLM content. The Define-XML v2.0 specification states that VLM should be applied when it provides information useful for interpreting study data, and that it need not be applied in all cases. Precisely what and where VLM should be used is determined by study implementers. Since there are no hard and fast rules describing when to use VLM, what should be included in a SHARE library of VLM content? It might be useful to ask, “where is VLM being used today?” Based on input so far, most implementers add VLM where they think the regulatory reviewers might want to see it. Since many organizations are not yet using Define-XML as a machine-readable specification, but are inst...

As part of the work to implement Value Level Metadata in SHARE, as well as to author a Define-XML Implementation Guide article, this will be the first of a series of posts on the topic of Value Level Metadata. These posts target a more technical audience, however the Define-XML IG article will include less technical jargon. Future posts will cover additional Value Level Metadata topics and examples. Value Level Metadata (VLM) is metadata that constrains a variable definition based on the value of another variable(s). VLM was originally specified in Define-XML v1.0 as a mechanism for providing the additional metadata needed for software to more accurately interpret these constrained variables.  For example, VSORRES is a variable with structural metadata of  DataType=”Text” and Length=”200”. However, when VSTESTCD=”DIABP” that definition is constrained by VLM to use DataType=”integer” and Length="3". In this case, the value of DIABP in VSTESTCD has triggered the application o...