diff --git a/openhtf/core/measurements.py b/openhtf/core/measurements.py
index b8f449f45..b05770a60 100644
--- a/openhtf/core/measurements.py
+++ b/openhtf/core/measurements.py
@@ -388,6 +388,8 @@ def __init__(self, description='', unit=units.NO_DIMENSION):
     })
 
   def __eq__(self, other):
+    if not issubclass(type(other), self.__class__):
+      return False
     return (self.description == other.description and self.unit == other.unit)
 
   def __ne__(self, other):