What’s in a SHARE Value Level Metadata Library?

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 instead creating it to fulfill an FDA submission requirement, implementers often add VLM for only the most very basic and obvious cases.  How should the SHARE VLM content be published so that it would be useful to implementers?  For those that are using VLM as a machine-readable specification, how are you using VLM?

A Proposal for Developing a VLM Library in SHARE

In line with current VLM usage, the SHARE team proposes to publish VLM for the most basic and obvious cases first. The VLM will be published as Define-XML v2.0 files and made available for download in eSHARE. Where available, the VLM will make use of the recent work on “CT Mapping/Alignment Across Codelists”, now posted on the CDISC website. These mapping specifications list sets of valid content for variables based on specific tests or parameters. For example, the “VS Test_Unit Codetable” specification provides the test name, valid units and valid positions for each VSTESTCD. Publishing these valid mapping specifications as VLM should provide the information in a useful format.

VLM in SHARE

As we publish the first sets of VLM, we’re interested in your feedback on the VLM content and format. Since VLM has largely been used as a study level deliverable, what content would make a useful VLM library? Look for an example VLM Define-XML v2.0 file on eSHARE in the next couple weeks. 

When implemented to its fullest extent, VLM will generate a significant amount of additional metadata. Managing this volume of additional detail could not be done adequately without a tool like SHARE. 

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