diff --git a/java/daikon/inv/binary/Member.java.jpp b/java/daikon/inv/binary/Member.java.jpp
index e9cb57b38..bc9dff09b 100644
--- a/java/daikon/inv/binary/Member.java.jpp
+++ b/java/daikon/inv/binary/Member.java.jpp
@@ -377,6 +377,9 @@ public final class CLASSNAME extends SEQUENCESCALAR {
 
   @Override
   protected double computeConfidence() {
+    if (ppt.num_samples() == 0) {
+      return Invariant.CONFIDENCE_UNJUSTIFIED;
+    }
     return Invariant.CONFIDENCE_JUSTIFIED;
   }
 
diff --git a/java/daikon/inv/binary/twoSequence/Reverse.java.jpp b/java/daikon/inv/binary/twoSequence/Reverse.java.jpp
index fd4fa0d21..5650837fd 100644
--- a/java/daikon/inv/binary/twoSequence/Reverse.java.jpp
+++ b/java/daikon/inv/binary/twoSequence/Reverse.java.jpp
@@ -222,6 +222,9 @@ public class CLASSNAME extends SUPERCLASS {
 
   @Override
   protected double computeConfidence() {
+    if (ppt.num_samples() == 0) {
+      return Invariant.CONFIDENCE_UNJUSTIFIED;
+    }
     return Invariant.CONFIDENCE_JUSTIFIED;
   }
 
diff --git a/java/daikon/inv/binary/twoSequence/SubSequence.java.jpp b/java/daikon/inv/binary/twoSequence/SubSequence.java.jpp
index c0b3e1898..74e1bcd91 100644
--- a/java/daikon/inv/binary/twoSequence/SubSequence.java.jpp
+++ b/java/daikon/inv/binary/twoSequence/SubSequence.java.jpp
@@ -308,6 +308,9 @@ public class CLASSNAME extends SUPERCLASS {
 
   @Override
   protected double computeConfidence() {
+    if (ppt.num_samples() == 0) {
+      return Invariant.CONFIDENCE_UNJUSTIFIED;
+    }
     return Invariant.CONFIDENCE_JUSTIFIED;
   }
 
diff --git a/java/daikon/inv/binary/twoSequence/SubSet.java.jpp b/java/daikon/inv/binary/twoSequence/SubSet.java.jpp
index 28f5ebe88..db3296df4 100644
--- a/java/daikon/inv/binary/twoSequence/SubSet.java.jpp
+++ b/java/daikon/inv/binary/twoSequence/SubSet.java.jpp
@@ -304,6 +304,9 @@ public class SUBSET extends TWOSEQUENCE {
 
   @Override
   protected double computeConfidence() {
+    if (ppt.num_samples() == 0) {
+      return Invariant.CONFIDENCE_UNJUSTIFIED;
+    }
     return Invariant.CONFIDENCE_JUSTIFIED;
   }
 
diff --git a/java/daikon/inv/unary/scalar/Range.java.jpp b/java/daikon/inv/unary/scalar/Range.java.jpp
index ce22729ed..5088f9409 100644
--- a/java/daikon/inv/unary/scalar/Range.java.jpp
+++ b/java/daikon/inv/unary/scalar/Range.java.jpp
@@ -185,6 +185,9 @@ public abstract class RANGE extends SUPERCLASS {
 
   @Override
   protected double computeConfidence() {
+    if (ppt.num_samples() == 0) {
+      return Invariant.CONFIDENCE_UNJUSTIFIED;
+    }
     return CONFIDENCE_JUSTIFIED;
   }