diff --git a/validations_common/callback_plugins/validation_json.py b/validations_common/callback_plugins/validation_json.py
index c5f1f84..1286f60 100644
--- a/validations_common/callback_plugins/validation_json.py
+++ b/validations_common/callback_plugins/validation_json.py
@@ -68,7 +68,7 @@ class CallbackModule(CallbackBase):
         self.results = []
         self.simple_results = []
         self.env = {}
-        self.t0 = None
+        self.start_time = None
         self.current_time = current_time()
 
     def _new_play(self, play):
@@ -115,7 +115,7 @@ class CallbackModule(CallbackBase):
         }
 
     def v2_playbook_on_start(self, playbook):
-        self.t0 = time.time()
+        self.start_time = time.time()
         pl = playbook._file_name
         validation_id = os.path.splitext(os.path.basename(pl))[0]
         self.env = {
@@ -181,7 +181,7 @@ class CallbackModule(CallbackBase):
             self.simple_results[-1]['task']['hosts'][host.name] = task_result
 
         end_time = current_time()
-        time_elapsed = secondsToStr(time.time() - self.t0)
+        time_elapsed = secondsToStr(time.time() - self.start_time)
         for result in self.results:
             if len(result['tasks']) > 1:
                 result['tasks'][-1]['task']['duration']['end'] = end_time
diff --git a/validations_common/callback_plugins/validation_stdout.py b/validations_common/callback_plugins/validation_stdout.py
index 83504f8..669689b 100644
--- a/validations_common/callback_plugins/validation_stdout.py
+++ b/validations_common/callback_plugins/validation_stdout.py
@@ -52,7 +52,7 @@ class CallbackModule(CallbackBase):
     def __init__(self, display=None):
         super(CallbackModule, self).__init__(display)
         self.env = {}
-        self.t0 = None
+        self.start_time = None
         self.current_time = current_time()
 
     def _new_play(self, play):
diff --git a/validations_common/tests/callback_plugins/test_validation_json.py b/validations_common/tests/callback_plugins/test_validation_json.py
index 768fbcc..6bd2def 100644
--- a/validations_common/tests/callback_plugins/test_validation_json.py
+++ b/validations_common/tests/callback_plugins/test_validation_json.py
@@ -90,7 +90,7 @@ class TestValidationJson(base.TestCase):
         self.assertEqual(callback.results, [])
         self.assertEqual(callback.simple_results, [])
         self.assertEqual(callback.env, {})
-        self.assertIsNone(callback.t0)
+        self.assertIsNone(callback.start_time)
         """
         Callback time sanity check only verifies general format
         of the stored time to be  iso format `YYYY-MM-DD HH:MM:SS.mmmmmm`
@@ -396,7 +396,7 @@ class TestValidationJson(base.TestCase):
         callback = validation_json.CallbackModule()
         callback.results = callback_results
         callback.simple_results = callback_simple_results
-        callback.t0 = 0
+        callback.start_time = 0
 
         callback._record_task_result(mock_on_info, mock_result)
 
diff --git a/validations_common/tests/callback_plugins/test_validation_stdout.py b/validations_common/tests/callback_plugins/test_validation_stdout.py
index d1d557a..2633713 100644
--- a/validations_common/tests/callback_plugins/test_validation_stdout.py
+++ b/validations_common/tests/callback_plugins/test_validation_stdout.py
@@ -91,7 +91,7 @@ class TestValidationStdout(base.TestCase):
         """
 
         self.assertEqual(callback.env, {})
-        self.assertIsNone(callback.t0)
+        self.assertIsNone(callback.start_time)
         """
         Callback time sanity check only verifies general format
         of the stored time to be  iso format `YYYY-MM-DD HH:MM:SS.mmmmmm`