diff --git a/moa/src/main/java/moa/evaluation/BasicConceptDriftPerformanceEvaluator.java b/moa/src/main/java/moa/evaluation/BasicConceptDriftPerformanceEvaluator.java
index d5df7cf06..ed4e02733 100644
--- a/moa/src/main/java/moa/evaluation/BasicConceptDriftPerformanceEvaluator.java
+++ b/moa/src/main/java/moa/evaluation/BasicConceptDriftPerformanceEvaluator.java
@@ -113,9 +113,8 @@ public void addResult(Example<Instance> example, double[] classVotes) {
                 }
             }
             //Compute error prediction
-            if (classVotes.length > 1) {
-                this.errorPrediction += Math.abs(classVotes[3] - inst.value(0));
-            }
+            this.errorPrediction += Math.abs(classVotes[3] - inst.value(0));
+            
         }
     }