diff --git a/etcdserver/membership/cluster.go b/etcdserver/membership/cluster.go
index 25c45dfce12..2330219f18a 100644
--- a/etcdserver/membership/cluster.go
+++ b/etcdserver/membership/cluster.go
@@ -178,7 +178,7 @@ func (c *RaftCluster) String() string {
 	fmt.Fprintf(b, "Members:[%s] ", strings.Join(ms, " "))
 	var ids []string
 	for id := range c.removed {
-		ids = append(ids, fmt.Sprintf("%s", id))
+		ids = append(ids, id.String())
 	}
 	fmt.Fprintf(b, "RemovedMemberIDs:[%s]}", strings.Join(ids, " "))
 	return b.String()
diff --git a/pkg/report/timeseries.go b/pkg/report/timeseries.go
index fcd9760638f..ee401eb9420 100644
--- a/pkg/report/timeseries.go
+++ b/pkg/report/timeseries.go
@@ -128,9 +128,9 @@ func (ts TimeSeries) String() string {
 	for i := range ts {
 		row := []string{
 			fmt.Sprintf("%d", ts[i].Timestamp),
-			fmt.Sprintf("%s", ts[i].MinLatency),
-			fmt.Sprintf("%s", ts[i].AvgLatency),
-			fmt.Sprintf("%s", ts[i].MaxLatency),
+			ts[i].MinLatency.String(),
+			ts[i].AvgLatency.String(),
+			ts[i].MaxLatency.String(),
 			fmt.Sprintf("%d", ts[i].ThroughPut),
 		}
 		rows = append(rows, row)