diff --git a/stochtree/config.py b/stochtree/config.py
index 6cf57cc5..7651e088 100644
--- a/stochtree/config.py
+++ b/stochtree/config.py
@@ -392,7 +392,7 @@ def get_sweep_update_indices(self) -> Union[np.ndarray,None]:
         sweep_update_indices : np.ndarray or None
             Vector of (0-indexed) indices of trees to update in a sweep, or `None`
         """
-        return self.feature_types
+        return self.sweep_update_indices
 
     def get_variable_weights(self) -> np.ndarray:
         """