Determining which Resources are appropriate for Activity to reference is not really possible until it has been in use for a while. At a minimum, add the following to the list of resources that can be referenced: Procedure, Encounter, Immunization, DiagnosticReport, and MedicationStatement. Note that the current list of acceptable references presupposes that the activities are always in the future. This may be appropriate when being used for clinical guidelines, but is not for an actual person's care plan. In a real care plan, the future inexorably becomes the past: What was an appointment becomes an encounter. What was a ProcedureRequest becomes a procedure.

This recommendation is a part of three separate recommendations (Make Activity a Separate Resource, Allow activity.reference to reference any resource, and Eliminate activity.detail), each of which would improve the usability of CarePlan for coordinating care between providers and between providers and patients. Without these changes it's very difficult to display the patient's upcoming schedule, or a list of activities one staff person or caregiver is responsible for, or a history of what has happened to, by or with the patient in the past. With these changes, these actions become a snap: Select all the Activity Resources for the desired time period, or for the desired performer. They also allow the patient's care plan to be the flexible always-changing collection of actions and events that care plans for people actually are.