diff --git a/src/unitxt/metrics.py b/src/unitxt/metrics.py
index 0aae6fef7..01269d457 100644
--- a/src/unitxt/metrics.py
+++ b/src/unitxt/metrics.py
@@ -513,6 +513,66 @@ def get_index_or_default(lst, item, default=-1):
         return default
 
 
+class AggregationReduction(Artifact, Generic[IntermediateType]):
+    def reduce(self, intermidates: List[IntermediateType]) -> Dict[str, Any]:
+        pass
+
+
+class DictReduction(AggregationReduction[Dict[str, float]]):
+    def reduce_list(self, lst: List[float]):
+        pass
+
+    def reduce(self, intermidates: List[Dict[str, float]]):
+        lists = {}
+        for intermidate in intermidates:
+            for key, val in intermidate.items():
+                if key not in lists:
+                    lists[key] = []
+                lists[key].append(val)
+
+        result = {}
+        for key, val_list in lists.items():
+            result[key] = self.reduce_list(val_list)
+        return result
+
+
+class MeanReduction(DictReduction):
+    def reduce_list(self, lst: List[float]):
+        return float(nan_mean(lst))
+
+
+class MaxReduction(DictReduction):
+    def reduce_list(self, lst: List[float]):
+        return float(nan_max(lst))
+
+
+class ReductionInstanceMetric(
+    MapReduceMetric[PredictionType, IntermediateType],
+    Generic[PredictionType, IntermediateType],
+):
+    reduction: AggregationReduction[IntermediateType]
+
+    def reduce(self, intermediates: List[IntermediateType]) -> Dict[str, Any]:
+        return self.reduction.reduce(intermediates)
+
+    def reduce_one(self, intermidate: IntermediateType):
+        return recursive_copy(intermidate)
+
+
+class AccuracyFast(ReductionInstanceMetric[str, Dict[str, float]]):
+    main_score = "accuracy"
+    reduction = MeanReduction()
+
+    def map(
+        self, prediction: str, references: List[str], task_data: Dict[str, Any]
+    ) -> Dict[str, float]:
+        return {
+            self.main_score: float(
+                str(prediction) in [str(reference) for reference in references]
+            )
+        }
+
+
 class F1Fast(MapReduceMetric[str, Tuple[int, int, List[str]]]):
     main_score = "f1"
 
diff --git a/tests/library/test_metrics.py b/tests/library/test_metrics.py
index 244865bfc..275a56578 100644
--- a/tests/library/test_metrics.py
+++ b/tests/library/test_metrics.py
@@ -7,6 +7,7 @@
 from unitxt.metrics import (
     NER,
     Accuracy,
+    AccuracyFast,
     BinaryAccuracy,
     BinaryMaxAccuracy,
     BinaryMaxF1,
@@ -215,6 +216,39 @@ def test_accuracy(self):
         for output, target in zip(outputs, instance_targets):
             self.assertDictEqual(output["score"]["instance"], target)
 
+    def test_accuracy_fast(self):
+        metric = AccuracyFast()
+
+        predictions = ["A", "B", "C"]
+        references = [["B", "C"], ["A"], ["B", "C"]]
+
+        outputs = apply_metric(
+            metric=metric, predictions=predictions, references=references
+        )
+
+        expected_global_result = {
+            "accuracy": 1 / 3,
+            "score": 1 / 3,
+            "score_name": "accuracy",
+        }
+
+        global_result = outputs[0]["score"]["global"].copy()
+        # Only check the keys that are expected, i.e. exist in expected_global_result
+        global_result = {
+            key: value
+            for key, value in global_result.items()
+            if key in expected_global_result
+        }
+        self.assertDictEqual(global_result, expected_global_result)
+
+        instance_targets = [
+            {"accuracy": 0.0, "score": 0.0, "score_name": "accuracy"},
+            {"accuracy": 0.0, "score": 0.0, "score_name": "accuracy"},
+            {"accuracy": 1.0, "score": 1.0, "score_name": "accuracy"},
+        ]
+        for output, target in zip(outputs, instance_targets):
+            self.assertDictEqual(output["score"]["instance"], target)
+
     def test_accuracy_with_prefix(self):
         metric = Accuracy(score_prefix="my_")
 
@@ -1335,6 +1369,14 @@ def test_instance_metric_confidence_interval(self):
             expected_ci_high=0.87,
         )
 
+    def test_map_reduce_metric_confidence_interval(self):
+        """Test the calculation of confidence intervals for an instance metric (Accuracy is used as an instance of an InstanceMetric)."""
+        self._test_confidence_interval(
+            metric=AccuracyFast(),
+            expected_ci_low=0.71,
+            expected_ci_high=0.87,
+        )
+
     def test_instance_metric_with_multiple_scores_confidence_interval(self):
         self._test_confidence_interval(
             metric=TokenOverlap(),
diff --git a/utils/.secrets.baseline b/utils/.secrets.baseline
index 03496ede1..9d171af9f 100644
--- a/utils/.secrets.baseline
+++ b/utils/.secrets.baseline
@@ -161,7 +161,7 @@
         "filename": "src/unitxt/metrics.py",
         "hashed_secret": "fa172616e9af3d2a24b5597f264eab963fe76889",
         "is_verified": false,
-        "line_number": 2370,
+        "line_number": 2430,
         "is_secret": false
       }
     ],
@@ -184,5 +184,5 @@
       }
     ]
   },
-  "generated_at": "2024-12-26T13:52:54Z"
+  "generated_at": "2024-12-26T14:29:31Z"
 }