diff --git a/SimPEG/Survey.py b/SimPEG/Survey.py
index 29bdb452..8abb547a 100644
--- a/SimPEG/Survey.py
+++ b/SimPEG/Survey.py
@@ -358,3 +358,4 @@ class BaseSurvey(object):
         noise = std*abs(self.dtrue)*np.random.randn(*self.dtrue.shape)
         self.dobs = self.dtrue+noise
         self.std = self.dobs*0 + std
+        return self.dobs