diff --git a/app/models/story.rb b/app/models/story.rb
index cdca475..1cb5d9b 100644
--- a/app/models/story.rb
+++ b/app/models/story.rb
@@ -18,15 +18,15 @@ class Story < ActiveRecord::Base
   # --- Permissions --- #
 
   def create_permitted?
-    acting_user.administrator?
+    project.creatable_by?(acting_user)
   end
 
   def update_permitted?
-    acting_user.signed_up? && !project_changed?
+    project.updatable_by?(acting_user)
   end
 
   def destroy_permitted?
-    acting_user.administrator?
+    project.destroyable_by?(acting_user)
   end
 
   def view_permitted?(field)
diff --git a/app/models/task.rb b/app/models/task.rb
index 76308f0..3a7a404 100644
--- a/app/models/task.rb
+++ b/app/models/task.rb
@@ -17,15 +17,15 @@ class Task < ActiveRecord::Base
   # --- Permissions --- #
 
   def create_permitted?
-    acting_user.administrator?
+    story.creatable_by?(acting_user)
   end
 
   def update_permitted?
-    acting_user.signed_up? && !story_changed?
+    story.updatable_by?(acting_user)
   end
 
   def destroy_permitted?
-    acting_user.administrator?
+    story.destroyable_by?(acting_user)
   end
 
   def view_permitted?(field)
diff --git a/app/models/task_assignment.rb b/app/models/task_assignment.rb
index b420c68..8f11a46 100644
--- a/app/models/task_assignment.rb
+++ b/app/models/task_assignment.rb
@@ -12,19 +12,19 @@ class TaskAssignment < ActiveRecord::Base
   # --- Permissions --- #
 
   def create_permitted?
-    acting_user.administrator?
+    task.creatable_by?(acting_user)
   end
 
   def update_permitted?
-    acting_user.administrator?
+    task.updatable_by?(acting_user)
   end
 
   def destroy_permitted?
-    acting_user.administrator?
+    task.destroyable_by?(acting_user)
   end
 
   def view_permitted?(field)
-    true
+    task.viewable_by?(acting_user)
   end
 
 end