diff --git a/domainlab/algos/observers/b_obvisitor.py b/domainlab/algos/observers/b_obvisitor.py
index 432da9703..d4ebc75d3 100644
--- a/domainlab/algos/observers/b_obvisitor.py
+++ b/domainlab/algos/observers/b_obvisitor.py
@@ -117,17 +117,7 @@ def cal_oracle_perf(self):
         """
         calculate oracle performance
         """
-        try:
-            model_or = self.host_trainer.model.load("oracle")
-            # @FIXME: name "oracle is a strong dependency
-            model_or = model_or.to(self.device)
-            model_or.eval()
-        except FileNotFoundError:
-            return {"acc_oracle": -1}
-        logger = Logger.get_logger()
-        logger.info("oracle model performance metric: \n")
-        metric_te = model_or.cal_perf_metric(self.loader_te, self.device)
-        return {"acc_oracle": metric_te["acc"]}
+        return self.exp.cal_oracle_perf()
 
     def dump_prediction(self, model_ld, metric_te):
         """
diff --git a/domainlab/exp/exp_main.py b/domainlab/exp/exp_main.py
index 12ecea5f5..29dc17be6 100755
--- a/domainlab/exp/exp_main.py
+++ b/domainlab/exp/exp_main.py
@@ -132,3 +132,20 @@ def clean_up(self):
             self.visitor.remove("ctr")  # pylint: disable=E1101
         except FileNotFoundError:
             pass
+
+    def cal_oracle_perf(self):
+        """
+        calculate oracle performance
+        """
+        try:
+            model_or = self.visitor.load("oracle")
+            # @FIXME: name "oracle is a strong dependency
+            model_or = model_or.to(self.device)
+            model_or.eval()
+        except FileNotFoundError:
+            return {"acc_oracle": -1}
+        logger = Logger.get_logger()
+        logger.info("oracle model performance metric: \n")
+        metric_te = model_or.cal_perf_metric(self.observer.loader_te,
+                                             self.device)
+        return {"acc_oracle": metric_te["acc"]}