Definition: An ACT that organizes a set of component acts into a semantic grouping that share a particular context such as timeframe, patient, etc.

UsageNotes: The focus in a GROUPER act is the grouping of the contained acts. For example "a request to group" (RQO), "a type of grouping that is allowed to occur" (DEF), etc.

Unlike WorkingList, which represents a dynamic, shared, continuously updated collection to provide a "view" of a set of objects, GROUPER collections tend to be static and simply indicate a shared set of semantics. Note that sharing of semantics can be achieved using ACT as well. However, with GROUPER, the sole semantic is of grouping.

**Description:**An ACT that organizes a set of component acts into a semantic grouping that have a shared subject. The subject may be either a subject participation (SBJ), subject act relationship (SUBJ), or child participation/act relationship types.

Discussion: The focus in a CLUSTER act is the grouping of the contained acts. For example "a request to cluster" (RQO), "a type of cluster that is allowed to occur" (DEF), etc.

Examples:

• Radiologic investigations that might include administration of a dye, followed by radiographic observations;
• "Isolate cluster" which includes all testing and specimen processing performed on a specific isolate;
• a set of actions to perform at a particular stage in a clinical trial.