diff --git a/src/java/org/apache/commons/math/estimation/SimpleEstimationProblem.java b/src/java/org/apache/commons/math/estimation/SimpleEstimationProblem.java
index b0e121dca..a5df84b72 100644
--- a/src/java/org/apache/commons/math/estimation/SimpleEstimationProblem.java
+++ b/src/java/org/apache/commons/math/estimation/SimpleEstimationProblem.java
@@ -41,7 +41,8 @@ public class SimpleEstimationProblem implements EstimationProblem {
      * Build an empty instance without parameters nor measurements.
      */
     public SimpleEstimationProblem() {
-        parameters = new ArrayList();
+        parameters   = new ArrayList();
+        measurements = new ArrayList();
     }
 
     public EstimatedParameter[] getAllParameters() {