diff --git a/bin/wm_cluster_remove_outliers.py b/bin/wm_cluster_remove_outliers.py
index b254933..571ce18 100755
--- a/bin/wm_cluster_remove_outliers.py
+++ b/bin/wm_cluster_remove_outliers.py
@@ -8,6 +8,7 @@
 
 import numpy as np
 import vtk
+from joblib import Parallel, delayed
 
 import whitematteranalysis as wma