diff --git a/specifications/schemas/demographic/Actor.yaml b/specifications/schemas/demographic/Actor.yaml
index a414eb9a..19565991 100644
--- a/specifications/schemas/demographic/Actor.yaml
+++ b/specifications/schemas/demographic/Actor.yaml
@@ -2,8 +2,6 @@ title: ACTOR
 type: object
 allOf:
   - $ref: ../demographic/Party.yaml
-required:
-  - languages
 properties:
   languages:
     type: array
diff --git a/specifications/schemas/demographic/Address.yaml b/specifications/schemas/demographic/Address.yaml
index fbf5b3a1..e7cbe373 100644
--- a/specifications/schemas/demographic/Address.yaml
+++ b/specifications/schemas/demographic/Address.yaml
@@ -2,6 +2,8 @@ title: ADDRESS
 type: object
 allOf:
   - $ref: ../common/Locatable.yaml
+required:
+  - details
 properties:
   details:
     $ref: ../data_structures/UItemStructure.yaml
diff --git a/specifications/schemas/demographic/Contact.yaml b/specifications/schemas/demographic/Contact.yaml
index 3710b021..4c405a58 100644
--- a/specifications/schemas/demographic/Contact.yaml
+++ b/specifications/schemas/demographic/Contact.yaml
@@ -2,6 +2,8 @@ title: CONTACT
 type: object
 allOf:
   - $ref: ../common/Locatable.yaml
+required:
+  - addresses
 properties:
   time_validity:
     $ref: ../data_types/DvIntervalOfDate.yaml
diff --git a/specifications/schemas/demographic/Party.yaml b/specifications/schemas/demographic/Party.yaml
index 771be8c5..40f4225d 100644
--- a/specifications/schemas/demographic/Party.yaml
+++ b/specifications/schemas/demographic/Party.yaml
@@ -2,6 +2,8 @@ title: PARTY
 type: object
 allOf:
   - $ref: ../common/Versionable.yaml
+required:
+  - identities
 properties:
   details:
     $ref: ../data_structures/UItemStructure.yaml
diff --git a/specifications/schemas/demographic/PartyIdentity.yaml b/specifications/schemas/demographic/PartyIdentity.yaml
index 2c305922..c77a79a6 100644
--- a/specifications/schemas/demographic/PartyIdentity.yaml
+++ b/specifications/schemas/demographic/PartyIdentity.yaml
@@ -2,6 +2,8 @@ title: PARTY_IDENTITY
 type: object
 allOf:
   - $ref: ../common/Locatable.yaml
+required:
+  - details
 properties:
   details:
     $ref: ../data_structures/UItemStructure.yaml
diff --git a/specifications/schemas/demographic/Role.yaml b/specifications/schemas/demographic/Role.yaml
index f2ece4ef..3263591e 100644
--- a/specifications/schemas/demographic/Role.yaml
+++ b/specifications/schemas/demographic/Role.yaml
@@ -3,8 +3,11 @@ type: object
 allOf:
   - $ref: ../demographic/Party.yaml
 required:
-  - languages
+  - performer
 properties:
+  _type:
+    type: string
+    default: ROLE
   time_validity:
     $ref: ../data_types/DvIntervalOfDate.yaml
   performer:
@@ -13,3 +16,4 @@ properties:
     type: array
     items:
       $ref: ../demographic/Capability.yaml
+x-discriminator-value: ROLE