diff --git a/src/main/java/com/ethlo/time/statistics/DurationPerformanceStatistics.java b/src/main/java/com/ethlo/time/statistics/DurationPerformanceStatistics.java
index 50201a2..88a3257 100644
--- a/src/main/java/com/ethlo/time/statistics/DurationPerformanceStatistics.java
+++ b/src/main/java/com/ethlo/time/statistics/DurationPerformanceStatistics.java
@@ -75,6 +75,10 @@ public Duration getStandardDeviation()
     {
         final IndexedCollection<Long> list = collectionStatistics.getList();
         final int count = list.size();
+        if (count == 0)
+        {
+            return Duration.ZERO;
+        }
         final double average = getAverage().toNanos();
         BigDecimal sd = BigDecimal.valueOf(0);
         for (long l : list)
diff --git a/src/main/java/com/ethlo/time/statistics/ThroughputPerformanceStatistics.java b/src/main/java/com/ethlo/time/statistics/ThroughputPerformanceStatistics.java
index 452ad18..ff38239 100644
--- a/src/main/java/com/ethlo/time/statistics/ThroughputPerformanceStatistics.java
+++ b/src/main/java/com/ethlo/time/statistics/ThroughputPerformanceStatistics.java
@@ -89,7 +89,7 @@ public Double getStandardDeviation()
         final int count = list.size();
         if (count == 0)
         {
-            return null;
+            return 0D;
         }
         final double average = getAverage();
         BigDecimal sd = BigDecimal.valueOf(0);