diff --git a/beacon_node/beacon_chain/src/test_utils.rs b/beacon_node/beacon_chain/src/test_utils.rs
index 0a2fd334d5..098408f70c 100644
--- a/beacon_node/beacon_chain/src/test_utils.rs
+++ b/beacon_node/beacon_chain/src/test_utils.rs
@@ -1280,7 +1280,7 @@ where
                         };
 
                         let subnet_id = SubnetId::compute_subnet_for_single_attestation::<E>(
-                            attestation.clone(),
+                            &attestation,
                             committee_count,
                             &self.chain.spec,
                         )
diff --git a/consensus/types/src/subnet_id.rs b/consensus/types/src/subnet_id.rs
index c010e12ff3..981d6d5653 100644
--- a/consensus/types/src/subnet_id.rs
+++ b/consensus/types/src/subnet_id.rs
@@ -61,7 +61,7 @@ impl SubnetId {
     /// Compute the subnet for an attestation where each slot in the
     /// attestation epoch contains `committee_count_per_slot` committees.
     pub fn compute_subnet_for_single_attestation<E: EthSpec>(
-        attestation: SingleAttestation,
+        attestation: &SingleAttestation,
         committee_count_per_slot: u64,
         spec: &ChainSpec,
     ) -> Result<SubnetId, ArithError> {