diff --git a/README.md b/README.md
index 5473b9a..98adda3 100644
--- a/README.md
+++ b/README.md
@@ -90,6 +90,7 @@ Contributed by [Yue Liao](yueliao.github.io), [Si Liu](http://colalab.org/people
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 2. For HICO-DET official evalution.
+The mAPs evaluated by our provided scripts are a bit lower (about 0.5% mAP)  than the official evaluation script.
 
 - Setup HICO-DET evaluation code: