diff --git a/nltools/data/design_matrix.py b/nltools/data/design_matrix.py
index 96c3b8a9..a94e1f9a 100644
--- a/nltools/data/design_matrix.py
+++ b/nltools/data/design_matrix.py
@@ -421,9 +421,6 @@ def add_dct_basis(self,duration=180):
 
         return out
 
-def all_same(items):
-    return np.all(x == items[0] for x in items)
-
 def _vif(X, y):
     """
         DEPRECATED