diff --git a/dnet-pace-core/src/main/java/eu/dnetlib/pace/condition/PidMatch.java b/dnet-pace-core/src/main/java/eu/dnetlib/pace/condition/PidMatch.java
index 4f9e0423d..a20ab9528 100644
--- a/dnet-pace-core/src/main/java/eu/dnetlib/pace/condition/PidMatch.java
+++ b/dnet-pace-core/src/main/java/eu/dnetlib/pace/condition/PidMatch.java
@@ -1,7 +1,11 @@
 package eu.dnetlib.pace.condition;
 
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
+import java.util.stream.Collectors;
 
+import com.google.common.collect.Sets;
 import eu.dnetlib.pace.config.Cond;
 import eu.dnetlib.pace.distance.eval.ConditionEval;
 import eu.dnetlib.pace.model.Field;
@@ -33,20 +37,21 @@ public class PidMatch extends AbstractCondition {
 		final List<Pid> pal = Pid.fromOafJson(sa);
 		final List<Pid> pbl = Pid.fromOafJson(sb);
 
-		int result = 0;
-		for(Pid pa : pal) {
-			final String ta = pa.getType();
+		final Set<String> pidAset = toHashSet(pal);
+		final Set<String> pidBset = toHashSet(pbl);
 
-			for(Pid pb : pbl) {
-				final String tb = pb.getType();
+		int incommon = Sets.intersection(pidAset, pidBset).size();
+		int simDiff = Sets.symmetricDifference(pidAset, pidBset).size();
 
-				if (tb.equalsIgnoreCase(ta)) {
-					result += pa.getValue().equalsIgnoreCase(pb.getValue()) ? 1 : -1;
-				}
-			}
-		}
+		int result = incommon / (incommon + simDiff) > 0.5 ? 1 : -1;
 
 		return new ConditionEval(cond, a, b, result);
 	}
 
+	private Set<String> toHashSet(List<Pid> pbl) {
+		return pbl.stream()
+					.map(pid -> pid.getType() + pid.getValue())
+					.collect(Collectors.toCollection(HashSet::new));
+	}
+
 }
diff --git a/dnet-pace-core/src/main/java/eu/dnetlib/pace/distance/algo/LevensteinDate.java b/dnet-pace-core/src/main/java/eu/dnetlib/pace/distance/algo/LevensteinDate.java
deleted file mode 100644
index 545295567..000000000
--- a/dnet-pace-core/src/main/java/eu/dnetlib/pace/distance/algo/LevensteinDate.java
+++ /dev/null
@@ -1,25 +0,0 @@
-package eu.dnetlib.pace.distance.algo;
-
-
-public class LevensteinDate extends Levenstein {
-
-
-	public LevensteinDate(double w) {
-		super(w);
-	}
-
-	
-	@Override
-	public double distance(String a, String b) {
-
-		return 1.0;
-	}
-	
-
-	
-	@Override
-	public double getWeight() {
-		return super.weight;
-	}
-
-}
diff --git a/dnet-pace-core/src/main/java/eu/dnetlib/pace/distance/algo/YearLevenstein.java b/dnet-pace-core/src/main/java/eu/dnetlib/pace/distance/algo/YearLevenstein.java
deleted file mode 100644
index 4e9796c2d..000000000
--- a/dnet-pace-core/src/main/java/eu/dnetlib/pace/distance/algo/YearLevenstein.java
+++ /dev/null
@@ -1,37 +0,0 @@
-package eu.dnetlib.pace.distance.algo;
-
-
-public class YearLevenstein extends SubStringLevenstein {
-
-	public YearLevenstein(double w) {
-		super(w);
-	}
-
-	public YearLevenstein(double w, int limit) {
-		super(w, limit);	
-	}
-	
-	@Override
-	public double distance(String a, String b) {
-		boolean check = checkLength(a) && checkLength(b);
-		if (check) {
-			if (a.equals(b)) {
-				return 1.0;
-			} else {
-				return 0.5;
-			}
-		} else {
-			return 1.0;
-		}
-	}
-	
-	protected boolean checkLength(String s) {
-		return getNumbers(s).length() == limit;
-	}
-	
-	@Override
-	public double getWeight() {
-		return super.weight;
-	}
-
-}
diff --git a/dnet-pace-core/src/main/java/eu/dnetlib/pace/model/FieldDef.java b/dnet-pace-core/src/main/java/eu/dnetlib/pace/model/FieldDef.java
index 8507b0cd7..5445053bd 100644
--- a/dnet-pace-core/src/main/java/eu/dnetlib/pace/model/FieldDef.java
+++ b/dnet-pace-core/src/main/java/eu/dnetlib/pace/model/FieldDef.java
@@ -83,8 +83,6 @@ public class FieldDef implements Serializable {
 			return new LevensteinTitle(getWeight());
 		case SubStringLevenstein:
 			return new SubStringLevenstein(getWeight(), getLimit());
-		case YearLevenstein:
-			return new YearLevenstein(getWeight(), getLimit());
 		case SortedJaroWinkler:
 			return new SortedJaroWinkler(getWeight());
 		case SortedLevel2JaroWinkler: