diff --git a/dhp-pace-core/src/main/java/eu/dnetlib/pace/tree/support/TreeNodeDef.java b/dhp-pace-core/src/main/java/eu/dnetlib/pace/tree/support/TreeNodeDef.java
index 0ff03f5e1..0973fdf1e 100644
--- a/dhp-pace-core/src/main/java/eu/dnetlib/pace/tree/support/TreeNodeDef.java
+++ b/dhp-pace-core/src/main/java/eu/dnetlib/pace/tree/support/TreeNodeDef.java
@@ -48,7 +48,7 @@ public class TreeNodeDef implements Serializable {
 	// function for the evaluation of the node
 	public TreeNodeStats evaluate(Row doc1, Row doc2, Config conf) {
 
-		TreeNodeStats stats = new TreeNodeStats(ignoreUndefined);
+		TreeNodeStats stats = new TreeNodeStats();
 
 		// for each field in the node, it computes the
 		for (FieldConf fieldConf : fields) {
diff --git a/dhp-pace-core/src/main/java/eu/dnetlib/pace/tree/support/TreeNodeStats.java b/dhp-pace-core/src/main/java/eu/dnetlib/pace/tree/support/TreeNodeStats.java
index f6b210a8c..2b96048b4 100644
--- a/dhp-pace-core/src/main/java/eu/dnetlib/pace/tree/support/TreeNodeStats.java
+++ b/dhp-pace-core/src/main/java/eu/dnetlib/pace/tree/support/TreeNodeStats.java
@@ -9,11 +9,8 @@ public class TreeNodeStats implements Serializable {
 
 	private Map<String, FieldStats> results; // this is an accumulator for the results of the node
 
-	private final boolean ignoreUndefined;
-
-	public TreeNodeStats(boolean ignoreUndefined) {
+	public TreeNodeStats() {
 		this.results = new HashMap<>();
-		this.ignoreUndefined = ignoreUndefined;
 	}
 
 	public Map<String, FieldStats> getResults() {
@@ -25,10 +22,7 @@ public class TreeNodeStats implements Serializable {
 	}
 
 	public int fieldsCount() {
-		if (ignoreUndefined)
-			return this.results.size();
-		else
-			return this.results.size() - undefinedCount(); // do not count undefined
+		return this.results.size();
 	}
 
 	public int undefinedCount() {
@@ -84,22 +78,11 @@ public class TreeNodeStats implements Serializable {
 		double min = 100.0; // random high value
 		for (FieldStats fs : this.results.values()) {
 			if (fs.getResult() < min) {
-				if (fs.getResult() == -1) {
-					if (fs.isCountIfUndefined()) {
-						min = 0.0;
-					} else {
-						min = -1;
-					}
-				} else {
+				if (fs.getResult() >= 0.0 || (fs.getResult() == -1 && fs.isCountIfUndefined()))
 					min = fs.getResult();
-				}
 			}
 		}
-		if (ignoreUndefined) {
-			return min == -1.0 ? 0.0 : min;
-		} else {
-			return min;
-		}
+		return min;
 	}
 
 	// if at least one is true, return 1.0
@@ -108,11 +91,7 @@ public class TreeNodeStats implements Serializable {
 			if (fieldStats.getResult() >= fieldStats.getThreshold())
 				return 1.0;
 		}
-		if (!ignoreUndefined && undefinedCount() > 0) {
-			return -1.0;
-		} else {
-			return 0.0;
-		}
+		return 0.0;
 	}
 
 	// if at least one is false, return 0.0
@@ -121,7 +100,7 @@ public class TreeNodeStats implements Serializable {
 
 			if (fieldStats.getResult() == -1) {
 				if (fieldStats.isCountIfUndefined())
-					return ignoreUndefined ? 0.0 : -1.0;
+					return 0.0;
 			} else {
 				if (fieldStats.getResult() < fieldStats.getThreshold())
 					return 0.0;
diff --git a/dhp-pace-core/src/main/java/eu/dnetlib/pace/tree/support/TreeProcessor.java b/dhp-pace-core/src/main/java/eu/dnetlib/pace/tree/support/TreeProcessor.java
index 28b3a82af..263504dbb 100644
--- a/dhp-pace-core/src/main/java/eu/dnetlib/pace/tree/support/TreeProcessor.java
+++ b/dhp-pace-core/src/main/java/eu/dnetlib/pace/tree/support/TreeProcessor.java
@@ -44,10 +44,12 @@ public class TreeProcessor {
 			TreeNodeStats stats = currentNode.evaluate(doc1, doc2, config);
 			treeStats.addNodeStats(nextNodeName, stats);
 
-			double finalScore = stats.getFinalScore(currentNode.getAggregation());
-			if (finalScore == -1.0)
+			// if ignoreUndefined=false the miss is considered as undefined
+			if (!currentNode.isIgnoreUndefined() && stats.undefinedCount() > 0) {
 				nextNodeName = currentNode.getUndefined();
-			else if (finalScore >= currentNode.getThreshold()) {
+			}
+			// if ignoreUndefined=true the miss is ignored and the score computed anyway
+			else if (stats.getFinalScore(currentNode.getAggregation()) >= currentNode.getThreshold()) {
 				nextNodeName = currentNode.getPositive();
 			} else {
 				nextNodeName = currentNode.getNegative();