diff --git a/source/core/aggregation-introduction.txt b/source/core/aggregation-introduction.txt
index 20b489ea1f3..40a960a9ef8 100644
--- a/source/core/aggregation-introduction.txt
+++ b/source/core/aggregation-introduction.txt
@@ -60,7 +60,7 @@ the custom JavaScript provide great flexibility compared to the
 aggregation pipeline, in general, map-reduce is less efficient and more
 complex than the aggregation pipeline.
 
-Additionally, map-reduce operations can have output sets that are that
+Additionally, map-reduce operations can have output sets that
 exceed the 16 megabyte output limitation of the aggregation pipeline.
 
 .. tip:: Starting in MongoDB 2.4, certain :program:`mongo` shell