diff --git a/src/main/java/envoy/event/GroupResizeEvent.java b/src/main/java/envoy/event/GroupResizeEvent.java
index af09c35..be5ac33 100644
--- a/src/main/java/envoy/event/GroupResizeEvent.java
+++ b/src/main/java/envoy/event/GroupResizeEvent.java
@@ -92,5 +92,5 @@ public class GroupResizeEvent extends Event<Long> {
 	 * {@inheritDoc}
 	 */
 	@Override
-	public String toString() { return String.format("GroupResizeEvent[userid=%d,groupid=%d,operation=%b]", get(), groupID, operation); }
+	public String toString() { return String.format("GroupResizeEvent[userid=%d,groupid=%d,operation=%s]", get(), groupID, operation); }
 }