diff --git a/apps/projects/helpers.py b/apps/projects/helpers.py
index 6b7d90bd8..52f4d2838 100644
--- a/apps/projects/helpers.py
+++ b/apps/projects/helpers.py
@@ -6,9 +6,6 @@
 from django.utils import timezone
 
 from adhocracy4.comments.models import Comment
-from adhocracy4.polls.models import Answer
-from adhocracy4.polls.models import Vote
-from adhocracy4.projects.models import Project
 from adhocracy4.reports.models import Report
 
 
@@ -44,31 +41,3 @@ def get_num_reported_unread_comments(project):
         .filter(num_reports__gt=0)
         .count()
     )
-
-
-def get_num_unregistered_participants(project: Project) -> int:
-    """Returns the number of unregistered users which participated in project.
-
-    Parameters
-    ----------
-    project : The project to get the number for.
-    """
-
-    answers = (
-        Answer.objects.filter(
-            question__poll__module__project=project, content_id__isnull=False
-        )
-        .values_list("content_id", flat=True)
-        .distinct()
-        .order_by()
-    )
-    votes = (
-        Vote.objects.filter(
-            choice__question__poll__module__project=project, content_id__isnull=False
-        )
-        .exclude(content_id__in=answers)
-        .values_list("content_id", flat=True)
-        .distinct()
-        .order_by()
-    )
-    return len(answers) + len(votes)
diff --git a/apps/projects/insights.py b/apps/projects/insights.py
index b3330a270..e01f6742a 100644
--- a/apps/projects/insights.py
+++ b/apps/projects/insights.py
@@ -1,6 +1,8 @@
 from typing import Iterable
 from typing import List
 
+from django.core.exceptions import FieldDoesNotExist
+
 from adhocracy4.polls.models import Answer
 from adhocracy4.polls.models import Poll
 from adhocracy4.polls.models import Vote
@@ -12,7 +14,6 @@
 from apps.interactiveevents.models import LiveQuestion
 from apps.mapideas.models import MapIdea
 from apps.projects.helpers import get_all_comments_project
-from apps.projects.helpers import get_num_unregistered_participants
 from apps.projects.models import ProjectInsight
 from apps.topicprio.models import Topic
 
@@ -27,7 +28,6 @@ def create_insight(project: Project) -> ProjectInsight:
     ideas = Idea.objects.filter(module__in=modules)
     map_ideas = MapIdea.objects.filter(module__in=modules)
     comments = get_all_comments_project(project=project)
-    unregistered_participants = get_num_unregistered_participants(project=project)
     proposals = Proposal.objects.filter(module__in=modules)
     polls = Poll.objects.filter(module__in=modules)
     votes = Vote.objects.filter(choice__question__poll__in=polls)
@@ -68,7 +68,6 @@ def create_insight(project: Project) -> ProjectInsight:
     insight, _ = ProjectInsight.objects.get_or_create(project=project)
 
     insight.comments = comments.count()
-    insight.unregistered_participants = unregistered_participants
     insight.ratings = sum(x.count() for x in rating_objects)
     insight.written_ideas = sum(x.count() for x in idea_objects)
     insight.poll_answers = votes.count() + answers.count()
@@ -76,8 +75,34 @@ def create_insight(project: Project) -> ProjectInsight:
     insight.save()
 
     insight.active_participants.clear()
+    unregistered_participants = set()
+
     for obj in creator_objects:
-        ids = list(obj.values_list("creator", flat=True).distinct().order_by())
+        # ignore objects which don't have a creator, they are counted in the next step.
+        ids = list(
+            obj.filter(creator__isnull=False)
+            .values_list("creator", flat=True)
+            .distinct()
+            .order_by()
+        )
         insight.active_participants.add(*ids)
+        # content from unregistered users doesn't have a creator but a content_id
+        if model_field_exists(obj.model, "content_id"):
+            content_ids = set(
+                obj.filter(content_id__isnull=False)
+                .values_list("content_id", flat=True)
+                .distinct()
+                .order_by()
+            )
+            unregistered_participants = unregistered_participants.union(content_ids)
 
+    insight.unregistered_participants = len(unregistered_participants)
     return insight
+
+
+def model_field_exists(cls, field):
+    try:
+        cls._meta.get_field(field)
+        return True
+    except FieldDoesNotExist:
+        return False