diff --git a/scripts/LBDatafile_schema.py b/scripts/LBDatafile_schema.py
index 9dca0276c5..a25f6d6e7e 100644
--- a/scripts/LBDatafile_schema.py
+++ b/scripts/LBDatafile_schema.py
@@ -8,7 +8,7 @@ def validate_ids(field):
     if 'seq_id' not in field and 'id' not in field:
         raise ValueError('Either id (bit-encoded) or seq_id must be provided.')
 
-    if field['migratable'] and 'seq_id' in field and 'collection_id' not in field:
+    if field.get("migratable") is True and 'seq_id' in field and 'collection_id' not in field:
         raise ValueError('If an entity is migratable, it must have a collection_id')
 
     return field