diff --git a/openbr/core/eval.cpp b/openbr/core/eval.cpp
index 8c8b70e..1a7159a 100755
--- a/openbr/core/eval.cpp
+++ b/openbr/core/eval.cpp
@@ -36,7 +36,12 @@ struct Comparison
     Comparison() {}
     Comparison(float _score, int _target, int _query, bool _genuine)
         : score(_score), target(_target), query(_query), genuine(_genuine) {}
-    inline bool operator<(const Comparison &other) const { return score > other.score; }
+
+    inline bool operator<(const Comparison &other) const
+    {
+        if (score != other.score) return (score > other.score);
+        else                      return !genuine; // Tie-break favors pessimistic behavior of ranking impostors higher.
+    }
 };
 
 #undef FAR // Windows preprecessor definition conflicts with variable name
@@ -183,7 +188,7 @@ float Evaluate(const Mat &simmat, const Mat &mask, const QString &csv, const QSt
     if (impostorCount == 0) qFatal("No impostor scores!");
 
     // Sort comparisons by simmat_val (score)
-    std::sort(comparisons.begin(), comparisons.end());
+    std::stable_sort(comparisons.begin(), comparisons.end());
 
     QList<OperatingPoint> operatingPoints;
     QList<float> genuines; genuines.reserve(sqrt((float)comparisons.size()));