diff --git a/ciw/node.py b/ciw/node.py
index b540b17..2b57e32 100644
--- a/ciw/node.py
+++ b/ciw/node.py
@@ -295,8 +295,8 @@ def find_number_of_slotted_services(self):
         Finds the number of slotted services to start in this slot
         """
         if self.schedule.capacitated:
-            return min(max(self.schedule.slot_size - self.number_in_service, 0), len(self.all_individuals))
-        return min(self.schedule.slot_size, len(self.all_individuals))
+            return min(max(self.schedule.slot_size - self.number_in_service, 0), self.number_of_individuals)
+        return min(self.schedule.slot_size, self.number_of_individuals)
 
     def interrupt_slotted_services(self):
         """
diff --git a/ciw/tests/test_simulation.py b/ciw/tests/test_simulation.py
index 8964952..a98e742 100644
--- a/ciw/tests/test_simulation.py
+++ b/ciw/tests/test_simulation.py
@@ -978,7 +978,7 @@ def my_baulking_function(n, Q=None, next_ind=None, next_node=None):
 
     def test_state_dependent_baulking(self):
         def my_baulking_function(n, Q, next_ind=None, next_node=None):
-            total_population = sum(len(node.all_individuals) for node in Q.transitive_nodes)
+            total_population = sum(node.number_of_individuals for node in Q.transitive_nodes)
             if total_population < 5:
                 return 0.0
             return 1.0