diff --git a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AccumulatingAggregatorFactory.java b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AccumulatingAggregatorFactory.java
index 3d52a45..acd766e 100644
--- a/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AccumulatingAggregatorFactory.java
+++ b/pregelix/pregelix-runtime/src/main/java/edu/uci/ics/pregelix/runtime/simpleagg/AccumulatingAggregatorFactory.java
@@ -180,7 +180,7 @@
                         throw new HyracksDataException(e);
                     }
                 }
-                return size;
+                return size * 2;
             }
 
             private void emitResultTuple(IFrameTupleAccessor accessor, int tIndex, AggregateState state)
@@ -224,4 +224,4 @@
 
         };
     }
-}
\ No newline at end of file
+}