diff --git a/src/mlpack/methods/neighbor_search/neighbor_search_rules_impl.hpp b/src/mlpack/methods/neighbor_search/neighbor_search_rules_impl.hpp
index 031965c36c..639483b996 100644
--- a/src/mlpack/methods/neighbor_search/neighbor_search_rules_impl.hpp
+++ b/src/mlpack/methods/neighbor_search/neighbor_search_rules_impl.hpp
@@ -183,7 +183,11 @@ inline double NeighborSearchRules<SortPolicy, MetricType, TreeType>::Score(
   }
   else
   {
-    adjustedScore = SortPolicy::CombineBest(adjustedScore, queryDescDist);
+    // If the parent node is NULL, force adjustedScore to be such that it can't
+    // be pruned.  Otherwise use the parent descendant distance.
+    const double queryParentDescDist = (queryNode.Parent() == NULL) ?
+        bestDistance : queryNode.Parent()->FurthestDescendantDistance();
+    adjustedScore = SortPolicy::CombineBest(adjustedScore, queryParentDescDist);
   }
 
   if (traversalInfo.LastReferenceNode() == referenceNode.Parent())
@@ -193,7 +197,11 @@ inline double NeighborSearchRules<SortPolicy, MetricType, TreeType>::Score(
   }
   else
   {
-    adjustedScore = SortPolicy::CombineBest(adjustedScore, refDescDist);
+    // If the parent node is NULL, force adjustedScore to be such that it can't
+    // be pruned.  Otherwise use the parent descendant distance.
+    const double refParentDescDist = (referenceNode.Parent() == NULL) ?
+        bestDistance : referenceNode.Parent()->FurthestDescendantDistance();
+    adjustedScore = SortPolicy::CombineBest(adjustedScore, refParentDescDist);
   }
 
   // Can we prune?