diff --git a/src/utilities/stats/file_io.py b/src/utilities/stats/file_io.py
index e7f8bf7b..fbb0a4fd 100644
--- a/src/utilities/stats/file_io.py
+++ b/src/utilities/stats/file_io.py
@@ -68,7 +68,7 @@ def save_best_ind_to_file(stats, ind, end=False, name="best"):
     savefile.write("Phenotype:\n" + str(ind.phenotype) + "\n\n")
     savefile.write("Genotype:\n" + str(ind.genome) + "\n")
     savefile.write("Tree:\n" + str(ind.tree) + "\n")
-    if hasattr(params['FITNESS_FUNCTION'], "training_test"):
+    if params["DATASET_TEST"]:
         if end:
             savefile.write("\nTraining fitness:\n" + str(ind.training_fitness))
             savefile.write("\nTest fitness:\n" + str(ind.test_fitness))