diff --git a/grakn-graql/src/main/java/ai/grakn/graql/internal/analytics/DegreeDistributionMapReduce.java b/grakn-graql/src/main/java/ai/grakn/graql/internal/analytics/DegreeDistributionMapReduce.java
index <HASH>..<HASH> 100644
--- a/grakn-graql/src/main/java/ai/grakn/graql/internal/analytics/DegreeDistributionMapReduce.java
+++ b/grakn-graql/src/main/java/ai/grakn/graql/internal/analytics/DegreeDistributionMapReduce.java
@@ -43,7 +43,9 @@ public class DegreeDistributionMapReduce extends GraknMapReduce<Set<String>> {
         if (selectedTypes.contains(Utility.getVertexType(vertex))) {
             emitter.emit(vertex.value(DegreeVertexProgram.DEGREE),
                     Collections.singleton(vertex.id().toString()));
+            return;
         }
+        emitter.emit(NullObject.instance(), Collections.emptySet());
     }
 
     @Override
Fix a bug causing StackOverflowError due to poor implementation of MapIterator of Tinkerpop (#<I>)