diff --git a/src/bayesvalidrox/post_processing/post_processing.py b/src/bayesvalidrox/post_processing/post_processing.py
index eb467c53adb1148d2116279d4acc1b8e5a7a9267..2fc4c84de15125a3d16910d916ba2fc7d78db98b 100644
--- a/src/bayesvalidrox/post_processing/post_processing.py
+++ b/src/bayesvalidrox/post_processing/post_processing.py
@@ -872,7 +872,10 @@ class PostProcessing:
             self.n_samples = samples.shape[0]
 
         # Evaluate the original and the surrogate model
-        y_val = self._eval_model(samples, key_str='valid')
+        if outputs is None:
+            y_val = self._eval_model(samples, key_str='valid')
+        else: 
+            y_val = outputs
         y_pce_val, _ = self.engine.eval_metamodel(samples=samples)
 
         # Open a pdf for the plots