diff --git a/source/reference/operator/aggregation/indexStats.txt b/source/reference/operator/aggregation/indexStats.txt
index 8d7c72e6722..59675c00b85 100644
--- a/source/reference/operator/aggregation/indexStats.txt
+++ b/source/reference/operator/aggregation/indexStats.txt
@@ -61,6 +61,13 @@ Definition
    Statistics for an index will be reset on :program:`mongod` restart
    or index drop and recreation.
 
+Behavior
+--------
+
+The statistics reported by the ``accesses`` field only includes index
+access driven by user requests. It does not include internal operations like 
+deletion via :doc:`/core/index-ttl` or chunk split and migration operations.
+
 Example
 -------