diff --git a/saqc/flagger/baseflagger.py b/saqc/flagger/baseflagger.py
index 9c6ba4fbe5a34ad11169600be7a4a13c42899495..edb275bbac2fdcfeb9faf199b741ee2b560f940a 100644
--- a/saqc/flagger/baseflagger.py
+++ b/saqc/flagger/baseflagger.py
@@ -36,6 +36,7 @@ class BaseFlagger(ABC):
     def __init__(self, dtype):
         # NOTE: the type of the _flags DictOfSeries
         self.dtype = dtype
+        self.extra_defaults = dict()
         # NOTE: the arggumens of setFlags supported from
         #       the configuration functions
         self.signature = ("flag",)
diff --git a/saqc/flagger/dmpflagger.py b/saqc/flagger/dmpflagger.py
index bb2eb8ef59807424c1c961aa00cb9d711b0a1b9d..42844b19ac79a59aaebb1573443853142ee8dbcc 100644
--- a/saqc/flagger/dmpflagger.py
+++ b/saqc/flagger/dmpflagger.py
@@ -38,6 +38,7 @@ class DmpFlagger(CategoricalFlagger):
     def __init__(self, **kwargs):
         super().__init__(FLAGS)
         self.flags_fields = [FlagFields.FLAG, FlagFields.CAUSE, FlagFields.COMMENT]
+        self.extra_defaults = dict(cause=FLAGS[0], comment="")
         self.signature = ("flag", "comment", "cause", "force")
 
         self._global_comments = kwargs