diff --git a/miplearn/components/steps/drop_redundant.py b/miplearn/components/steps/drop_redundant.py
index 1eadfff..f22cb6c 100644
--- a/miplearn/components/steps/drop_redundant.py
+++ b/miplearn/components/steps/drop_redundant.py
@@ -45,6 +45,10 @@ class DropRedundantInequalitiesStep(Component):
         self.violation_tolerance = violation_tolerance
         self.max_iterations = max_iterations
         self.current_iteration = 0
+        self.total_dropped = 0
+        self.total_restored = 0
+        self.total_kept = 0
+        self.total_iterations = 0
 
     def before_solve(self, solver, instance, _):
         self.current_iteration = 0
@@ -62,7 +66,7 @@ class DropRedundantInequalitiesStep(Component):
         self.total_iterations = 0
         for category in y.keys():
             for i in range(len(y[category])):
-                if y[category][i][0] == 1:
+                if y[category][i][1] == 1:
                     cid = constraints[category][i]
                     c = LazyConstraint(
                         cid=cid,
@@ -101,7 +105,7 @@ class DropRedundantInequalitiesStep(Component):
         for category in tqdm(x.keys(), desc="Fit (rlx:drop_ineq)"):
             if category not in self.classifiers:
                 self.classifiers[category] = deepcopy(self.classifier_prototype)
-            self.classifiers[category].fit(x[category], y[category])
+            self.classifiers[category].fit(x[category], np.array(y[category]))
 
     @staticmethod
     def _x_test(instance, constraint_ids):
@@ -160,9 +164,9 @@ class DropRedundantInequalitiesStep(Component):
                     if category not in y:
                         y[category] = []
                     if slack > self.slack_tolerance:
-                        y[category] += [[1]]
+                        y[category] += [[False, True]]
                     else:
-                        y[category] += [[0]]
+                        y[category] += [[True, False]]
         return y
 
     def predict(self, x):
@@ -175,9 +179,9 @@ class DropRedundantInequalitiesStep(Component):
             proba = self.classifiers[category].predict_proba(x_cat)
             for i in range(len(proba)):
                 if proba[i][1] >= self.threshold:
-                    y[category] += [[1]]
+                    y[category] += [[False, True]]
                 else:
-                    y[category] += [[0]]
+                    y[category] += [[True, False]]
         return y
 
     def evaluate(self, instance):
@@ -187,13 +191,13 @@ class DropRedundantInequalitiesStep(Component):
         tp, tn, fp, fn = 0, 0, 0, 0
         for category in y_true.keys():
             for i in range(len(y_true[category])):
-                if y_pred[category][i][0] == 1:
-                    if y_true[category][i][0] == 1:
+                if y_pred[category][i][1] == 1:
+                    if y_true[category][i][1] == 1:
                         tp += 1
                     else:
                         fp += 1
                 else:
-                    if y_true[category][i][0] == 1:
+                    if y_true[category][i][1] == 1:
                         fn += 1
                     else:
                         tn += 1
diff --git a/tests/components/steps/test_drop_redundant.py b/tests/components/steps/test_drop_redundant.py
index 8e4c329..d673b1a 100644
--- a/tests/components/steps/test_drop_redundant.py
+++ b/tests/components/steps/test_drop_redundant.py
@@ -6,11 +6,13 @@ from unittest.mock import Mock, call
 
 import numpy as np
 
+from miplearn import RelaxIntegralityStep, BasePyomoSolver
 from miplearn.classifiers import Classifier
 from miplearn.components.steps.drop_redundant import DropRedundantInequalitiesStep
 from miplearn.instance import Instance
 from miplearn.solvers.internal import InternalSolver
 from miplearn.solvers.learning import LearningSolver
+from tests.solvers import _get_knapsack_instance
 
 
 def _setup():
@@ -268,8 +270,20 @@ def test_x_y_fit_predict_evaluate():
         ),
     }
     expected_y = {
-        "type-a": np.array([[0], [0], [1]]),
-        "type-b": np.array([[1], [0], [0]]),
+        "type-a": np.array(
+            [
+                [True, False],
+                [True, False],
+                [False, True],
+            ]
+        ),
+        "type-b": np.array(
+            [
+                [False, True],
+                [True, False],
+                [True, False],
+            ]
+        ),
     }
 
     # Should build X and Y matrices correctly
@@ -287,7 +301,15 @@ def test_x_y_fit_predict_evaluate():
         np.testing.assert_array_equal(actual_x, expected_x[category])
         np.testing.assert_array_equal(actual_y, expected_y[category])
 
-    assert component.predict(expected_x) == {"type-a": [[1]], "type-b": [[0], [1]]}
+    assert component.predict(expected_x) == {
+        "type-a": [
+            [False, True],
+        ],
+        "type-b": [
+            [True, False],
+            [False, True],
+        ],
+    }
 
     ev = component.evaluate(instances[1])
     assert ev["True positive"] == 1
@@ -350,8 +372,20 @@ def test_x_multiple_solves():
     }
 
     expected_y = {
-        "type-a": np.array([[1], [0], [0], [1]]),
-        "type-b": np.array([[1], [0]]),
+        "type-a": np.array(
+            [
+                [False, True],
+                [True, False],
+                [True, False],
+                [False, True],
+            ]
+        ),
+        "type-b": np.array(
+            [
+                [False, True],
+                [True, False],
+            ]
+        ),
     }
 
     # Should build X and Y matrices correctly
@@ -362,3 +396,17 @@ def test_x_multiple_solves():
     for category in ["type-a", "type-b"]:
         np.testing.assert_array_equal(actual_x[category], expected_x[category])
         np.testing.assert_array_equal(actual_y[category], expected_y[category])
+
+
+def test_usage():
+    solver = LearningSolver(
+        components=[
+            RelaxIntegralityStep(),
+            DropRedundantInequalitiesStep(),
+        ]
+    )
+    instance = _get_knapsack_instance(BasePyomoSolver)
+    # The following should not crash
+    solver.solve(instance)
+    solver.fit([instance])
+    solver.solve(instance)