Page History

Grouping variables are

...

Identifier and Grouping Qualifier variables used to group records in

...

datasets

...

. 

Hierarchy of Grouping Variables

• STUDYID
  • DOMAIN
    • --CAT
      • --SCAT
        • USUBJID
          • --GRPID
            • --REFID

How Grouping Variables Group Data

1. For the subject
   1. All records with the same USUBJID value are a group of records that describe that subject.
2. Across subjects (records with different USUBJID values)
   1. All records with the same STUDYID value are a group of records that describe that study.
   2. All records with the same DOMAIN value are a group of records that describe that domain.
3. --CAT and --SCAT values further subset groups of tests within a domain and are not redundant with the domain or dictionary classification provided by --DECOD and --BODSYS. Generally, --CAT/--SCAT values have meaning within a particular domain

...

1. and apply to all subjects within that domain. For example, a lab record with LBTEST = "SODIUM" might have LBCAT = "CHEMISTRY" and LBSCAT = "ELECTROLYTES". 
   1. --GRPID values further group (subset) records within USUBJID. Unlike --CAT and --SCAT, --GRPID values are not intended to have any meaning across subjects and they are usually assigned during or after data collection.
   2. Although --SPID and --REFID are identifier variables, these are usually not considered to be grouping variables, although they may have meaning across domains.

Differences Between Grouping Variables

1. The primary distinctions between -CAT/ SCAT and --GRPID are:
   1. --CAT/ SCAT are known (identified) about the data before it is collected. --CAT/ SCAT values group data across subjects. --CAT/-SCAT may have some controlled terminology.
   2. --GRPID is usually assigned during or after data collection at the discretion of the sponsor. --GRPID groups data only within a subject. --GRPID values are sponsor-defined and are not be subject to controlled terminology.
2. The primary distinction between -CAT/ SCAT and --REFID is that --CAT/-SCAT are usually textual descriptions of the data designed into the collection vehicle/process, and --REFID is usually a tracking number/value of some type assigned to an object being tracked (e.g., a blood sample).

In domains based on the Findings general observation class, the --RESCAT variable can be used to categorize results after the fact. --CAT and --SCAT by contrast, are generally predefined or used at the point of collection, not after assessing the value of findings results

...

.

...

...