CDISC遞交數(shù)據(jù)--Value Level Metadata實例續(xù)講
Spec：
Vlm：
Acrf：
Vlm是什么？
是define.xml里的一種用于表示CDISC標(biāo)準(zhǔn)中獨立定義的變量之間關(guān)系的實施方法。
什么時候考慮使用vlm？
Define-XML 2.0 Specification:
?Used where the dataset variable metadata?does not provide sufficient detail?to support data review and analysis
?Value Level Metadata should be provided?when there is a need?to describe differing metadata attributes for subsets of cells within a column
使用Vlm好處是什么？
Value level = Row level，每條記錄提供的細(xì)節(jié)可以support clear, unambiguous documentation.
對于Reviewer：提供研究數(shù)據(jù)相關(guān)的有用的信息。
對于programmer：描述某些變量該如何編程。
Vlm和CT應(yīng)該是預(yù)先根據(jù)crf就決定好的，如果數(shù)據(jù)中出現(xiàn)了unexpected?values or new concepts，那么就可以進(jìn)一步檢查Vlm和CT。
可以發(fā)現(xiàn)出有問題的值，然后再做進(jìn)一步的檢查。
Define-XML 2.0 Specification:
?Value Level Metadata should be applied when it provides information useful for interpreting study data. It need not be applied in all cases.
?It is left to the discretion of the creator when it is useful to provide Value Level Metadata and when it is not.
哪里使用VLM？
Standard Use Cases（從下圖總結(jié)，可結(jié)合我文末鏈接文章閱讀。）
1.Findings Test Codes?note: IE exception
2.Supplemental Qualifiers（QVAL）系統(tǒng)自動生成
3.Multiple Origins
Define-XML 2.0 Specification / Phuse guidance:
?When deciding whether or not to define VLM,? a good rule of thumb is that if providing VLM for a variable would mean each value has a codelist containing? only one CodeList Item, it is probably more appropriate to define a codelist rather than a valuelist.?? [ This is the case with --TEST and --TESTCD Variables]
比如LBTEST只需要給codelist，而LBORRES就要給vlm。
Note：
如果是一些很重要的數(shù)據(jù)，比如一些Role為topic變量也可以為其提供vlm，不僅僅是限制于findingsdomains的result變量。比如interventions的cmtrt。一般來說finding類的最重要的變量就是orres，即result，當(dāng)我們在描述result的時候通常使用TESTCD，但是比如lborres往往會有上百條testcd。為了簡潔，其余變量無需重復(fù)使用vlm。但是一些變量如果有特別的需求也可以使用，比如表達(dá)lborres數(shù)據(jù)來源。
拓展：
Codelist：
When a variable has value-level specified and value-level items have different codelists associated with them, the codelists should be provided on the value-level definition.
Define-XML 2.0 Specification:
When a variable has value-level metadata specified and all value-level definitions have the same codelist associated with them, the codelist should be provided on the variable-level.
