diff --git a/pallets/distance/src/lib.rs b/pallets/distance/src/lib.rs
index 45ee644be46120edc2ea2c1dac8c5dc8864a09f8..5a47d2ae5ff01571c33429ff7a116a4479255b22 100644
--- a/pallets/distance/src/lib.rs
+++ b/pallets/distance/src/lib.rs
@@ -66,6 +66,7 @@ pub mod pallet {
             <Self::Currency as frame_support::traits::Currency<Self::AccountId>>::Balance,
         >;
         /// Minimum ratio of accessible referees
+        #[pallet::constant]
         type MinAccessibleReferees: Get<Perbill>;
         /// Number of session to keep a positive evaluation result
         type ResultExpiration: Get<u32>;