For <action-execution-policy>, you can specify individual or collective as the value. It determines whether an action must be executed in the context of a specific visitor or visitors (individual), or if it can be executed once for an entire collection of visitors participating in a scenario (collective). For example, the SendEmail action is marked as individual because it must have a person to whom the e-mail is sent. On the other hand, the RecordEvent action is collective, because it simply records event information to a dataset, regardless of who is going through the scenario.