diff --git a/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineAdaBoost.java b/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineAdaBoost.java
index 98276ff75..0bde95042 100644
--- a/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineAdaBoost.java
+++ b/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineAdaBoost.java
@@ -227,7 +227,9 @@ protected void adjustEnsembleSize(int nClasses) {
     		for (int i = this.nEstimators; i < nClasses; i++) {
     			this.ensemble.add(this.baseLearner.copy()); 
     			this.nEstimators ++;
-    			this.adwinEnsemble.add(new ADWIN());
+                if (this.driftDetection) {
+                    this.adwinEnsemble.add(new ADWIN());
+                }
     			this.lambdaSc.add(0.0);
                 this.lambdaSw.add(0.0);
                 this.epsilon.add(0.0);               
diff --git a/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineAdaC2.java b/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineAdaC2.java
index 110370401..7048033a1 100644
--- a/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineAdaC2.java
+++ b/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineAdaC2.java
@@ -256,7 +256,9 @@ protected void adjustEnsembleSize(int nClasses) {
     		for (int i = this.nEstimators; i < nClasses; i++) {
     			this.ensemble.add(this.baseLearner.copy()); 
     			this.nEstimators ++;
-    			this.adwinEnsemble.add(new ADWIN());
+                if (this.driftDetection) {
+                    this.adwinEnsemble.add(new ADWIN());
+                }
     			this.lambdaTP.add(0.0);
                 this.lambdaTN.add(0.0);
                 this.lambdaFP.add(0.0);
diff --git a/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineCSB2.java b/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineCSB2.java
index f7fb8575a..f84805014 100644
--- a/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineCSB2.java
+++ b/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineCSB2.java
@@ -249,7 +249,9 @@ protected void adjustEnsembleSize(int nClasses) {
     		for (int i = this.nEstimators; i < nClasses; i++) {
     			this.ensemble.add(this.baseLearner.copy()); 
     			this.nEstimators ++;
-    			this.adwinEnsemble.add(new ADWIN());    			
+                if (this.driftDetection) {
+                    this.adwinEnsemble.add(new ADWIN());
+                }
     			this.lambdaFP.add(0.0);
                 this.lambdaFN.add(0.0);
                 this.lambdaSum.add(0.0);
diff --git a/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineRUSBoost.java b/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineRUSBoost.java
index 80bd2e828..f9b93d5ea 100644
--- a/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineRUSBoost.java
+++ b/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineRUSBoost.java
@@ -291,7 +291,9 @@ protected void adjustEnsembleSize(int nClasses) {
     		for (int i = this.nEstimators; i < nClasses; i++) {
     			this.ensemble.add(this.baseLearner.copy()); 
     			this.nEstimators ++;
-    			this.adwinEnsemble.add(new ADWIN());
+				if (this.driftDetection) {
+					this.adwinEnsemble.add(new ADWIN());
+				}
     			this.lambdaSc.add(0.0);
                 this.lambdaPos.add(0.0);
                 this.lambdaNeg.add(0.0);
diff --git a/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineSMOTEBagging.java b/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineSMOTEBagging.java
index f4191a558..eaaf8b1ef 100644
--- a/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineSMOTEBagging.java
+++ b/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineSMOTEBagging.java
@@ -231,7 +231,9 @@ protected void adjustEnsembleSize(int nClasses) {
     		for (int i = this.nEstimators; i < nClasses; i++) {
     			this.ensemble.add(this.baseLearner.copy()); 
     			this.nEstimators ++;
-    			this.adwinEnsemble.add(new ADWIN());    			
+				if (this.driftDetection) {
+					this.adwinEnsemble.add(new ADWIN());
+				}
 			}
     	}
     }
diff --git a/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineUnderOverBagging.java b/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineUnderOverBagging.java
index aed93282f..9235dfe5c 100644
--- a/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineUnderOverBagging.java
+++ b/moa/src/main/java/moa/classifiers/meta/imbalanced/OnlineUnderOverBagging.java
@@ -209,7 +209,9 @@ protected void adjustEnsembleSize(int nClasses) {
     		for (int i = this.nEstimators; i < nClasses; i++) {
     			this.ensemble.add(this.baseLearner.copy()); 
     			this.nEstimators ++;
-    			this.adwinEnsemble.add(new ADWIN());    			
+                if (this.driftDetection) {
+                    this.adwinEnsemble.add(new ADWIN());
+                }
 			}
     	}
     }