diff --git a/alma/experiment.py b/alma/experiment.py
index 07446ce..7696916 100644
--- a/alma/experiment.py
+++ b/alma/experiment.py
@@ -46,7 +46,7 @@ class Dispatcher (threading.Thread):
         self.__exp_mod = exp_mod
 
         for i in range(self.__num_workers):
-            self.__workers.append(Worker(exp_mod, exp_plan))
+            self.__workers.append(Worker(exp_mod, exp_plan, i))
 
     def run(self):
         for worker in self.__workers:
@@ -93,11 +93,12 @@ class Dispatcher (threading.Thread):
 
 
 class Worker (multiprocessing.Process):
-    def __init__(self, exp_mod, exp_plan):
+    def __init__(self, exp_mod, exp_plan, id):
         multiprocessing.Process.__init__(self)
         
         self.__exp_mod = exp_mod
         self.__exp_plan = exp_plan
+        self.__id = id
 
     def run(self):
         instance = self.__exp_plan.next()
@@ -110,7 +111,8 @@ class Worker (multiprocessing.Process):
                                    instance,
                                    data
                                 ), 
-                               instance_state)
+                               instance_state,
+                               worker_id=self.__id)
             
             self.__exp_plan.done_with(instance)