This code system http://hl7.org/fhir/goal-priority defines the following codes:

CodeDisplayDefinition
high-priorityHigh PriorityIndicates that the goal is of considerable importance and should be a primary focus of care delivery.
medium-priorityMedium PriorityIndicates that the goal has a reasonable degree of importance and that concrete action should be taken towards the goal. Attainment is not as critical as high-priority goals.
low-priorityLow PriorityThe goal is desirable but is not sufficiently important to devote significant resources to. Achievement of the goal may be sought when incidental to achieving other goals.