The specific assignment of group codes depends on the item being described in the file. However, the type of the value this group supplies is derived from the group code in the following way:
Group Codes are used both to indicate the type of the value of the group, as explained earlier, and to indicate the general use of the group. The specific function of the group code depends on the actual variable, table item, or entity description. The following table indicates the general use of groups, noting as “fixed” any that always have the same function.
