diff --git a/core/metric.py b/core/metric.py
index ae91cd6de35e11ccbd2c7bd5f3d4b745c8723a4f..12a9ddf79d5a0821f0e6c6d9195bf51a63ebd6fb 100755
--- a/core/metric.py
+++ b/core/metric.py
@@ -69,8 +69,8 @@ class Metric(object):
         global_metrics = dict()
         for key in self._global_metric_state_vars:
             varname, dtype = self._global_metric_state_vars[key]
-            global_metrics[key] = self.get_global_metric_state(fleet, scope,
-                                                               varname)
+            global_metrics[key] = self._get_global_metric_state(fleet, scope,
+                                                                varname)
 
         return self._calculate(global_metrics)