diff --git a/participants/prepare_usernames_file.py b/participants/prepare_usernames_file.py
new file mode 100644
index 0000000..75f463c
--- /dev/null
+++ b/participants/prepare_usernames_file.py
@@ -0,0 +1,14 @@
+import datetime
+
+import participants.query_db
+
+participants_inactive_usernames = participants.query_db.get_usernames(
+    tester=False,  # True participants are wanted.
+    active=False,  # They have all finished their participation.
+    collection_start=datetime.date.fromisoformat(
+        "2020-08-01"
+    ),  # This is the timeframe of the main study.
+    last_upload=datetime.date.fromisoformat("2021-09-01"),
+)
+
+print(participants_inactive_usernames.__len__())