diff --git a/coleman4hcs/reward.py b/coleman4hcs/reward.py
index 4d313c5..b510e8f 100644
--- a/coleman4hcs/reward.py
+++ b/coleman4hcs/reward.py
@@ -123,12 +123,23 @@ def get_name(self):
         return 'RNFail'
 
     def evaluate(self, reward: EvaluationMetric, last_prioritization: List[str]):
-        if not reward.detected_failures:
+        """
+        Evaluate rewards based on failures.
+
+        :param reward: Evaluation metric containing detection ranks and scheduled test cases.
+        :param last_prioritization: Test case names in prioritization order.
+        :return: List of rewards for each test case in the prioritization.
+        """
+        if not reward.detection_ranks:
+            # No failing test cases: All rewards are 0
             return [0.0] * len(last_prioritization)
 
-        rank_idx = np.array(reward.detection_ranks) - 1
-        rewards = np.zeros(len(reward.scheduled_testcases))
-        rewards[rank_idx] = 1
+        # Convert detection ranks to 0-based indices
+        failing_indices = set(reward.detection_ranks)
 
-        return [rewards[reward.scheduled_testcases.index(tc)] if tc in reward.scheduled_testcases else 0.0 for tc in
-                last_prioritization]
+        # Assign rewards: 1 for failing test cases, 0 otherwise
+        rewards = [
+            1.0 if i + 1 in failing_indices else 0.0
+            for i, tc in enumerate(last_prioritization)
+        ]
+        return rewards
diff --git a/coleman4hcs/tests/test_reward.py b/coleman4hcs/tests/test_reward.py
index 7ea49d8..306feaa 100644
--- a/coleman4hcs/tests/test_reward.py
+++ b/coleman4hcs/tests/test_reward.py
@@ -113,3 +113,57 @@ def test_rn_fail_reward_no_failures(mock_empty_evaluation_metric, sample_priorit
     reward = RNFailReward()
     results = reward.evaluate(mock_empty_evaluation_metric, sample_prioritization)
     assert np.allclose(results, [0.0] * len(sample_prioritization))
+
+
+@pytest.mark.benchmark
+def test_time_rank_reward_performance(benchmark):
+    """
+    Performance test for TimeRankReward evaluation method.
+    This test evaluates the performance of the reward function for larger datasets.
+    """
+    # Mocking a large dataset
+    num_testcases = 10000
+    detection_ranks = list(range(1, num_testcases + 1, 2))  # Failures at odd indices
+    scheduled_testcases = [f"Test{i}" for i in range(1, num_testcases + 1)]
+    sample_prioritization = scheduled_testcases  # Assume prioritization is the same as scheduling
+
+    # Mocking EvaluationMetric
+    mock_metric = MagicMock(spec=EvaluationMetric)
+    mock_metric.detection_ranks = detection_ranks
+    mock_metric.scheduled_testcases = scheduled_testcases
+
+    reward = TimeRankReward()
+
+    # Benchmark the evaluation method
+    def run_evaluation():
+        reward.evaluate(mock_metric, sample_prioritization)
+
+    benchmark(run_evaluation)
+
+
+@pytest.mark.benchmark
+def test_rn_fail_reward_performance(benchmark):
+    """
+    Performance test for RNFailReward evaluation method.
+    This test evaluates the performance of the reward function for larger datasets.
+    """
+    # Mocking a large dataset
+    num_testcases = 10000
+    detection_ranks = list(range(1, num_testcases + 1, 2))  # Failures at odd indices
+    scheduled_testcases = [f"Test{i}" for i in range(1, num_testcases + 1)]
+    sample_prioritization = scheduled_testcases  # Assume prioritization is the same as scheduling
+
+    # Mocking EvaluationMetric
+    mock_metric = MagicMock(spec=EvaluationMetric)
+    mock_metric.detection_ranks = detection_ranks
+    mock_metric.scheduled_testcases = scheduled_testcases
+    mock_metric.detected_failures = True
+
+    reward = RNFailReward()
+
+    # Benchmark the evaluation method
+    def run_evaluation():
+        reward.evaluate(mock_metric, sample_prioritization)
+
+    benchmark(run_evaluation)
+