diff --git a/src/main/java/org/opennars/lab/metric/MetricReporter.java b/src/main/java/org/opennars/lab/metric/MetricReporter.java
index 7598af211ea15fa94e93ba17da6707b284f3d917..7b2d6f97073d3568e9c8e4f8a3644aa037e9d670 100644
--- a/src/main/java/org/opennars/lab/metric/MetricReporter.java
+++ b/src/main/java/org/opennars/lab/metric/MetricReporter.java
@@ -11,7 +11,7 @@ import java.util.*;
  */
 public class MetricReporter {
     public String narsVersion = Nar.VERSION;
-    public long runId =  Calendar.getInstance().getTimeInMillis();
+    public int runId = (int)Calendar.getInstance().getTimeInMillis();
 
     public List<MetricObserver> observers = new ArrayList<>();