diff --git a/toolkit.py b/toolkit.py
index 5ac5fff1d9a9798481b9f5bd9e190a97a3abb697..c58f005dbe29c774a4342edb37d392587b3d4797 100755
--- a/toolkit.py
+++ b/toolkit.py
@@ -2060,7 +2060,7 @@ class ClassificationProjectDecorr(ClassificationProject):
             bin_idx = np.digitize(out, binning)
             # include overflow into last bin
             bin_idx[bin_idx==len(binning)] = len(binning)-1
-            out_list[i+1] = keras.utils.to_categorical(bin_idx)
+            out_list[i+1] = keras.utils.to_categorical(bin_idx, num_classes=len(binning))
         return out_list