This code system http://terminology.hl7.org/CodeSystem/activity-definition-category defines the following codes:

CodeDisplayDefinition
treatment TreatmentThe activity is intended to provide or is related to treatment of the patient.
education EducationThe activity is intended to provide or is related to education of the patient.
assessment AssessmentThe activity is intended to perform or is related to assessment of the patient.
 <status value="draft"/> <experimental value="false"/> <date value="2020-04-09T21:10:28+00:00"/> <publisher value="HL7 (FHIR Project)"/> <contact> <telecom> <system value="url"/> <value value="http://hl7.org/fhir"/> </telecom> <telecom> <system value="email"/> <value value="fhir@lists.hl7.org"/> </telecom> </contact> <description value="High-level categorization of the type of activity."/> <caseSensitive value="true"/> <valueSet value="http://terminology.hl7.org/ValueSet/activity-definition-category"/> <content value="complete"/> <concept> <code value="treatment"/> <display value="Treatment"/> <definition value="The activity is intended to provide or is related to treatment of the patient."/> </concept> <concept> <code value="education"/> <display value="Education"/> <definition value="The activity is intended to provide or is related to education of the patient."/> </concept> <concept> <code value="assessment"/> <display value="Assessment"/> <definition value="The activity is intended to perform or is related to assessment of the patient."/> </concept> </CodeSystem>