diff --git a/analysis/ros_processor.py b/analysis/ros_processor.py
index cf69b6f..17e436c 100644
--- a/analysis/ros_processor.py
+++ b/analysis/ros_processor.py
@@ -22,7 +22,7 @@ class RosProcessor():
         # TODO add other stuff
         # Instances of callback_start for eventual matching
         self._callback_starts = {}
-        # Callback instances, callback_address: end - start
+        # Callback instances, callback_address: (end - start, start)
         self.callbacks_instances = {}
 
         # Link a ROS trace event to its corresponding handling method
@@ -72,4 +72,4 @@ class RosProcessor():
         start_timestamp = self._callback_starts.pop(callback_addr, None)
         if start_timestamp is not None:
             duration = metadata.timestamp - start_timestamp
-            self.callbacks_instances[callback_addr].append(duration)
+            self.callbacks_instances[callback_addr].append((duration, start_timestamp))
diff --git a/analysis/to_pandas.py b/analysis/to_pandas.py
index 9806759..2496913 100644
--- a/analysis/to_pandas.py
+++ b/analysis/to_pandas.py
@@ -6,12 +6,15 @@ from .ros_processor import RosProcessor
 def callback_durations_to_df(ros_processor):
     callback_addresses = []
     durations = []
+    start_timestamps = []
     for addr in ros_processor.callbacks_instances:
-        for d in ros_processor.callbacks_instances[addr]:
+        for duration, start in ros_processor.callbacks_instances[addr]:
             callback_addresses.append(addr)
-            durations.append(d)
+            durations.append(duration)
+            start_timestamps.append(start)
 
     return pd.DataFrame(data={
         'callback_address': callback_addresses,
         'duration': durations,
+        'start_timestamp': start_timestamps
     })