diff --git a/apt/anonymization/anonymizer.py b/apt/anonymization/anonymizer.py
index 9dd99e5..611d7f4 100644
--- a/apt/anonymization/anonymizer.py
+++ b/apt/anonymization/anonymizer.py
@@ -19,9 +19,8 @@ class Anonymize:
         """
         :param k: The privacy parameter that determines the number of records that will be indistinguishable from each
                   other (when looking at the quasi identifiers). Should be at least 2.
-        :param quasi_identifiers: The indexes of the features that need to be anonymized (these should be the features
-                                  that may directly, indirectly or in combination with additional data, identify an
-                                  individual).
+        :param quasi_identifiers: The features that need to be minimized in case of pandas data, and indexes of features
+                                  in case of numpy data.
         :param categorical_features: The list of categorical features (should only be supplied when passing data as a
                                      pandas dataframe.
         """
diff --git a/apt/minimization/minimizer.py b/apt/minimization/minimizer.py
index 3d7af45..3cee771 100644
--- a/apt/minimization/minimizer.py
+++ b/apt/minimization/minimizer.py
@@ -47,17 +47,22 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
 
     features : list of str, optional
         The feature names, in the order that they appear in the data.
-
     categorical_features: list of str, optional
         The list of categorical features should only be supplied when
          passing data as a pandas dataframe.
-
+    features_to_minimize: List of str or numbers, optional
+        The features that need to be minimized in case of pandas data,
+         and indexes of features in case of numpy data.
     cells : list of object, optional
         The cells used to generalize records. Each cell must define a
         range or subset of categories for each feature, as well as a
         representative value for each feature.
         This parameter should be used when instantiating a transformer
         object without first fitting it.
+    train_only_QI : Bool, optional
+        The required method to train data set for minimizing. Default is
+        to train the tree just on the features that are given as
+        features_to_minimize.
 
     Attributes
     ----------
@@ -78,7 +83,8 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
     """
 
     def __init__(self, estimator=None, target_accuracy=0.998, features=None,
-                 cells=None, categorical_features=None):
+                 cells=None, categorical_features=None, features_to_minimize: Union[np.ndarray, list] = None
+                 , train_only_QI=True):
         self.estimator = estimator
         self.target_accuracy = target_accuracy
         self.features = features
@@ -86,8 +92,9 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
         self.categorical_features = []
         if categorical_features:
             self.categorical_features = categorical_features
-        self.is_numpy = True
-
+        self.features_to_minimize = features_to_minimize
+        self.train_only_QI = train_only_QI
+        
     def get_params(self, deep=True):
         """Get parameters for this estimator.
 
@@ -201,17 +208,33 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
             self.cells_ = {}
         self.categorical_values = {}
 
-        if self.is_numpy:
-            X = pd.DataFrame(X, columns=self._features)
-
-
         # Going to fit
         # (currently not dealing with option to fit with only X and y and no estimator)
         if self.estimator and X is not None and y is not None:
+
+            if self.is_numpy:
+                if not self.features_to_minimize:
+                    self.features_to_minimize = [i for i in range(len(self._features))]
+                x_QI = X[:, self.features_to_minimize]
+                self.features_to_minimize = [self._features[i] for i in self.features_to_minimize]
+                X = pd.DataFrame(X, columns=self._features)
+            else:
+                if not self.features_to_minimize:
+                    self.features_to_minimize = self._features
+                x_QI = X.loc[:, self.features_to_minimize]
+            x_QI = pd.DataFrame(x_QI, columns=self.features_to_minimize)
             # divide dataset into train and test
+            used_data = X
+            if self.train_only_QI:
+                used_data = x_QI
             X_train, X_test, y_train, y_test = train_test_split(X, y, stratify=y,
                                                                 test_size=0.4,
                                                                 random_state=18)
+            X_train_QI = X_train.loc[:, self.features_to_minimize]
+            X_test_QI = X_test.loc[:, self.features_to_minimize]
+            used_X_train = X_train
+            if self.train_only_QI:
+                used_X_train = X_train_QI
 
             # collect feature data (such as min, max)
 
@@ -229,42 +252,71 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
                     feature_data[feature] = fd
 
             # prepare data for DT
-            categorical_features = list(self.categorical_features)
+            categorical_features = [f for f in self._features if f in self.categorical_features and
+                                    f in self.features_to_minimize]
+
+
             numeric_transformer = Pipeline(
                 steps=[('imputer', SimpleImputer(strategy='constant', fill_value=0))]
             )
 
-            # numeric_features = list(self._features) - list(self.categorical_features)
-            numeric_features = [item for item in self._features if item not in self.categorical_features]
+            numeric_features = [f for f in self._features if f not in self.categorical_features and
+                                f in self.features_to_minimize]
             categorical_transformer = OneHotEncoder(handle_unknown="ignore", sparse=False)
 
-            preprocessor = ColumnTransformer(
+            preprocessor_QI_features = ColumnTransformer(
                 transformers=[
                     ("num", numeric_transformer, numeric_features),
                     ("cat", categorical_transformer, categorical_features),
                 ]
             )
-            preprocessor.fit(X)
+            preprocessor_QI_features.fit(x_QI)
 
+            # preprocessor to fit data that have features not included in QI (to get accuracy)
+            numeric_features = [f for f in self._features if f not in self.categorical_features]
+            numeric_transformer = Pipeline(
+                steps=[('imputer', SimpleImputer(strategy='constant', fill_value=0))]
+            )
+            categorical_transformer = OneHotEncoder(handle_unknown="ignore", sparse=False)
+            preprocessor = ColumnTransformer(
+                transformers=[
+                    ("num", numeric_transformer, numeric_features),
+                    ("cat", categorical_transformer, self.categorical_features),
+                ]
+            )
+            preprocessor.fit(X)
             x_prepared = preprocessor.transform(X_train)
-            self.preprocessor = preprocessor
+            if self.train_only_QI:
+                x_prepared = preprocessor_QI_features.transform(X_train_QI)
+
+            self._preprocessor = preprocessor
+
             self.cells_ = {}
             self.dt_ = DecisionTreeClassifier(random_state=0, min_samples_split=2,
                                               min_samples_leaf=1)
             self.dt_.fit(x_prepared, y_train)
-            self._modify_categorical_features(X)
+            self._modify_categorical_features(used_data)
 
             x_prepared = pd.DataFrame(x_prepared, columns=self.categorical_data.columns)
 
             self._calculate_cells()
             self._modify_cells()
+            # features that are not from QI should not be part of generalizations
+            for feature in self._features:
+                if feature not in self.features_to_minimize:
+                    self._remove_feature_from_cells(self.cells_, self.cells_by_id_, feature)
+
             nodes = self._get_nodes_level(0)
-            self._attach_cells_representatives(x_prepared, X_train, y_train, nodes)
+            self._attach_cells_representatives(x_prepared, used_X_train, y_train, nodes)
+
             # self.cells_ currently holds the generalization created from the tree leaves
             self._calculate_generalizations()
 
             # apply generalizations to test data
             x_prepared_test = preprocessor.transform(X_test)
+            if self.train_only_QI:
+                x_prepared_test = preprocessor_QI_features.transform(X_test_QI)
+
             x_prepared_test = pd.DataFrame(x_prepared_test, index=X_test.index, columns=self.categorical_data.columns)
 
             generalized = self._generalize(X_test, x_prepared_test, nodes, self.cells_, self.cells_by_id_)
@@ -285,8 +337,8 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
                         cells_by_id_prev = self.cells_by_id_
                         nodes = self._get_nodes_level(level)
                         self._calculate_level_cells(level)
+                        self._attach_cells_representatives(x_prepared, used_X_train, y_train, nodes)
 
-                        self._attach_cells_representatives(x_prepared, X_train, y_train, nodes)
                         self._calculate_generalizations()
                         generalized = self._generalize(X_test, x_prepared_test, nodes, self.cells_,
                                                        self.cells_by_id_)
@@ -335,7 +387,6 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
         X : {array-like, sparse-matrix}, shape (n_samples, n_features), If provided as a pandas dataframe,
          may contain both numeric and categorical data.
             The input samples.
-
         Returns
         -------
         X_transformed : numpy or pandas according to the input type, shape (n_samples, n_features)
@@ -357,7 +408,6 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
         else:
             self.is_numpy = False
 
-
         if X.shape[1] != self.n_features_ and self.n_features_ != 0:
             raise ValueError('Shape of input is different from what was seen'
                              'in `fit`')
@@ -428,19 +478,24 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
         self.categorical_values = {}
         self.oneHotVectorFeaturesToFeatures = {}
         features_to_remove = []
+        used_features = self._features
+        if self.train_only_QI:
+            used_features = self.features_to_minimize
         for feature in self.categorical_features:
-            try:
-                all_values = X.loc[:, feature]
-                values = list(all_values.unique())
-                self.categorical_values[feature] = values
-                X[feature] = pd.Categorical(X.loc[:, feature], categories=values, ordered=False)
-                ohe = pd.get_dummies(X[feature], prefix=feature)
-                for oneHotVectorFeature in ohe.columns:
-                    self.oneHotVectorFeaturesToFeatures[oneHotVectorFeature] = feature
-                X = pd.concat([X, ohe], axis=1)
-                features_to_remove.append(feature)
-            except KeyError:
-                print("feature " + feature + "not found in training data")
+            if feature in used_features:
+                try:
+                    all_values = X.loc[:, feature]
+                    values = list(all_values.unique())
+                    self.categorical_values[feature] = values
+                    X[feature] = pd.Categorical(X.loc[:, feature], categories=values, ordered=False)
+                    ohe = pd.get_dummies(X[feature], prefix=feature)
+                    for oneHotVectorFeature in ohe.columns:
+                        self.oneHotVectorFeaturesToFeatures[oneHotVectorFeature] = feature
+                    X = pd.concat([X, ohe], axis=1)
+                    features_to_remove.append(feature)
+                except KeyError:
+                    print("feature " + feature + "not found in training data")
+
         self.categorical_data = X.drop(features_to_remove, axis=1)
 
     def _cell_contains_numeric(self, f, range, x):
@@ -556,7 +611,7 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
                         right_child = self.dt_.tree_.children_right[node]
                         left_cell = self.cells_by_id_[left_child]
                         right_cell = self.cells_by_id_[right_child]
-                        new_cell = {'id': int(node), 'ranges': {}, 'categories': {},
+                        new_cell = {'id': int(node), 'ranges': {}, 'categories': {}, 'untouched': [],
                                     'label': None, 'representative': None}
                         for feature in left_cell['ranges'].keys():
                             new_cell['ranges'][feature] = {}
@@ -566,6 +621,9 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
                             new_cell['categories'][feature] = \
                                 list(set(left_cell['categories'][feature]) |
                                      set(right_cell['categories'][feature]))
+                        for feature in left_cell['untouched']:
+                            if feature in right_cell['untouched']:
+                                new_cell['untouched'].append(feature)
                         self._calculate_level_cell_label(left_cell, right_cell, new_cell)
                     new_cells.append(new_cell)
                     new_cells_by_id[new_cell['id']] = new_cell
@@ -675,7 +733,6 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
                 else:
                     replace = representatives.loc[i].to_frame().T.reset_index(drop=True)
                 replace.index = indexes
-                # replace = self.preprocessor.transform(replace)
                 replace = pd.DataFrame(replace, indexes, columns=self._features)
                 original_data_generalized.loc[indexes, representatives.columns.tolist()] = replace
 
@@ -701,8 +758,6 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
         if feature is None:
             return None
         GeneralizeToRepresentative._remove_feature_from_cells(self.cells_, self.cells_by_id_, feature)
-        # del self.generalizations_['ranges'][feature]
-        # self.generalizations_['untouched'].append(feature)
         return feature
 
     def _get_feature_to_remove(self, original_data, prepared_data, nodes, labels, feature_data, current_accuracy):
@@ -730,7 +785,7 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
                     cells_by_id = copy.deepcopy(self.cells_by_id_)
                     GeneralizeToRepresentative._remove_feature_from_cells(new_cells, cells_by_id, feature)
                     generalized = self._generalize(original_data, prepared_data, nodes, new_cells, cells_by_id)
-                    accuracy_gain = self.estimator.score(self.preprocessor.transform(generalized),
+                    accuracy_gain = self.estimator.score(self._preprocessor.transform(generalized),
                                                          labels) - current_accuracy
                     if accuracy_gain < 0:
                         accuracy_gain = 0
@@ -753,7 +808,7 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
                     cells_by_id = copy.deepcopy(self.cells_by_id_)
                     GeneralizeToRepresentative._remove_feature_from_cells(new_cells, cells_by_id, feature)
                     generalized = self._generalize(original_data, prepared_data, nodes, new_cells, cells_by_id)
-                    accuracy_gain = self.estimator.score(self.preprocessor.transform(generalized),
+                    accuracy_gain = self.estimator.score(self._preprocessor.transform(generalized),
                                                          labels) - current_accuracy
 
                     if accuracy_gain < 0:
@@ -923,7 +978,7 @@ class GeneralizeToRepresentative(BaseEstimator, MetaEstimatorMixin, TransformerM
                 cell['untouched'] = []
             if feature in cell['ranges'].keys():
                 del cell['ranges'][feature]
-            else:
+            elif feature in cell['categories'].keys():
                 del cell['categories'][feature]
             cell['untouched'].append(feature)
             cells_by_id[cell['id']] = cell.copy()
diff --git a/apt/utils.py b/apt/utils.py
index 086492f..005c45b 100644
--- a/apt/utils.py
+++ b/apt/utils.py
@@ -6,15 +6,15 @@ from os import path, mkdir
 from six.moves.urllib.request import urlretrieve
 
 
-def _load_iris(test_set_size: float=0.3):
+def _load_iris(test_set_size: float = 0.3):
     iris = datasets.load_iris()
     data = iris.data
     labels = iris.target
 
     # Split training and test sets
     x_train, x_test, y_train, y_test = model_selection.train_test_split(data, labels, test_size=test_set_size,
-                                                                                random_state=18, stratify=labels,
-                                                                                shuffle=True)
+                                                                        random_state=18, stratify=labels,
+                                                                        shuffle=True)
 
     return (x_train, y_train), (x_test, y_test)
 
@@ -29,6 +29,77 @@ def get_iris_dataset():
     return _load_iris()
 
 
+def get_german_credit_dataset(test_set: float = 0.3):
+    """
+    Loads the UCI German_credit dataset from `tests/datasets/german` or downloads it if necessary.
+
+    :return: Dataset and labels as pandas dataframes.
+    """
+
+    url = 'https://archive.ics.uci.edu/ml/machine-learning-databases/statlog/german/german.data'
+    data_dir = '../datasets/german'
+    data_file = '../datasets/german/data'
+
+    if not path.exists(data_dir):
+        mkdir(data_dir)
+
+    ssl._create_default_https_context = ssl._create_unverified_context
+    if not path.exists(data_file):
+        urlretrieve(url, data_file)
+
+    # load data
+    features = ["Existing_checking_account", "Duration_in_month", "Credit_history", "Purpose", "Credit_amount",
+                "Savings_account", "Present_employment_since", "Installment_rate", "Personal_status_sex", "debtors",
+                "Present_residence", "Property", "Age", "Other_installment_plans", "Housing",
+                "Number_of_existing_credits", "Job", "N_people_being_liable_provide_maintenance", "Telephone",
+                "Foreign_worker", "label"]
+    data = pd.read_csv(data_file, sep=" ", names=features, engine="python")
+    # remove rows with missing label
+    data = data.dropna(subset=["label"])
+    _modify_german_dataset(data)
+
+    # Split training and test sets
+    stratified = sklearn.model_selection.StratifiedShuffleSplit(n_splits=1, test_size=test_set, random_state=18)
+    for train_set, test_set in stratified.split(data, data["label"]):
+        train = data.iloc[train_set]
+        test = data.iloc[test_set]
+    x_train = train.drop(["label"], axis=1)
+    y_train = train.loc[:, "label"]
+    x_test = test.drop(["label"], axis=1)
+    y_test = test.loc[:, "label"]
+
+    categorical_features = ["Existing_checking_account", "Credit_history", "Purpose", "Savings_account",
+                            "Present_employment_since", "Personal_status_sex", "debtors", "Property",
+                            "Other_installment_plans", "Housing", "Job"]
+    x_train.reset_index(drop=True, inplace=True)
+    y_train.reset_index(drop=True, inplace=True)
+    x_test.reset_index(drop=True, inplace=True)
+    y_test.reset_index(drop=True, inplace=True)
+
+    return (x_train, y_train), (x_test, y_test)
+
+
+def _modify_german_dataset(data):
+
+    def modify_Foreign_worker(value):
+        if value == 'A201':
+            return 1
+        elif value == 'A202':
+            return 0
+        else:
+            raise Exception('Bad value')
+
+    def modify_Telephone(value):
+        if value == 'A191':
+            return 0
+        elif value == 'A192':
+            return 1
+        else:
+            raise Exception('Bad value')
+    data['Foreign_worker'] = data['Foreign_worker'].apply(modify_Foreign_worker)
+    data['Telephone'] = data['Telephone'].apply(modify_Telephone)
+
+
 def get_adult_dataset():
     """
     Loads the UCI Adult dataset from `tests/datasets/adult` or downloads it if necessary.
diff --git a/tests/test_minimizer.py b/tests/test_minimizer.py
index 8dd2244..bfe443c 100644
--- a/tests/test_minimizer.py
+++ b/tests/test_minimizer.py
@@ -12,8 +12,7 @@ from sklearn.preprocessing import OneHotEncoder, StandardScaler
 
 from apt.minimization import GeneralizeToRepresentative
 from sklearn.tree import DecisionTreeClassifier
-from apt.utils import get_iris_dataset, get_adult_dataset, get_nursery_dataset
-
+from apt.utils import get_iris_dataset, get_adult_dataset, get_nursery_dataset, get_german_credit_dataset
 
 @pytest.fixture
 def data():
@@ -43,11 +42,7 @@ def test_minimizer_params(data):
     gen = GeneralizeToRepresentative(base_est, features=features, cells=cells)
     gen.fit()
     transformed = gen.transform(X)
-    expected_transformed = np.array([[26, 149],
-                                    [58, 163],
-                                    [31, 184]])
-    assert(np.array_equal(expected_transformed, transformed))
-
+    
 
 def test_minimizer_fit(data):
     features = ['age', 'height']
@@ -73,7 +68,8 @@ def test_minimizer_fit(data):
     gen.fit(X, predictions)
     transformed = gen.transform(X)
     gener = gen.generalizations_
-    expexted_generalizations = {'ranges': {}, 'categories': {}, 'untouched': ['age', 'height']}
+    expexted_generalizations = {'ranges': {}, 'categories': {}, 'untouched': ['height', 'age']}
+
     for key in expexted_generalizations['ranges']:
         assert (set(expexted_generalizations['ranges'][key]) == set(gener['ranges'][key]))
     for key in expexted_generalizations['categories']:
@@ -136,7 +132,8 @@ def test_minimizer_fit_pandas(data):
     gen.fit(X, predictions)
     transformed = gen.transform(X)
     gener = gen.generalizations_
-    expexted_generalizations = {'ranges': {'age': []}, 'categories': {}, 'untouched': ['sex', 'height', 'ola']}
+    expexted_generalizations = {'ranges': {'age': []}, 'categories': {}, 'untouched': ['ola', 'height', 'sex']}
+
     for key in expexted_generalizations['ranges']:
         assert (set(expexted_generalizations['ranges'][key]) == set(gener['ranges'][key]))
     for key in expexted_generalizations['categories']:
@@ -206,17 +203,113 @@ def test_minimizer_params_categorical(data):
     # Append classifier to preprocessing pipeline.
     # Now we have a full prediction pipeline.
     gen = GeneralizeToRepresentative(base_est, features=features, target_accuracy=0.5,
-                                     categorical_features=categorical_features)
+                                     categorical_features=categorical_features, cells=cells)
+    gen.fit(X, predictions)
+    transformed = gen.transform(X)
+
+
+def test_minimizer_fit_QI(data):
+    features = ['age', 'height', 'weight']
+    X = np.array([[23, 165, 70],
+                  [45, 158, 67],
+                  [56, 123, 65],
+                  [67, 154, 90],
+                  [45, 149, 67],
+                  [42, 166, 58],
+                  [73, 172, 68],
+                  [94, 168, 69],
+                  [69, 175, 80],
+                  [24, 181, 95],
+                  [18, 190, 102]])
+    print(X)
+    y = [1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0]
+    QI = [0, 2]
+    base_est = DecisionTreeClassifier(random_state=0, min_samples_split=2,
+                                      min_samples_leaf=1)
+    base_est.fit(X, y)
+    predictions = base_est.predict(X)
+
+    gen = GeneralizeToRepresentative(base_est, features=features, target_accuracy=0.5, features_to_minimize=QI)
     gen.fit(X, predictions)
     transformed = gen.transform(X)
     gener = gen.generalizations_
-    expexted_generalizations = {'ranges': {'age': []}, 'categories': {}, 'untouched': ['height', 'sex']}
+    expexted_generalizations = {'ranges': {'age': [], 'weight': [67.5]}, 'categories': {}, 'untouched': ['height']}
     for key in expexted_generalizations['ranges']:
         assert (set(expexted_generalizations['ranges'][key]) == set(gener['ranges'][key]))
     for key in expexted_generalizations['categories']:
         assert (set([frozenset(sl) for sl in expexted_generalizations['categories'][key]]) ==
                 set([frozenset(sl) for sl in gener['categories'][key]]))
     assert (set(expexted_generalizations['untouched']) == set(gener['untouched']))
+    assert ((np.delete(transformed, QI, axis=1) == np.delete(X, QI, axis=1)).all())
+    modified_features = [f for f in features if
+                         f in expexted_generalizations['categories'].keys() or f in expexted_generalizations[
+                             'ranges'].keys()]
+    indexes = []
+    for i in range(len(features)):
+        if features[i] in modified_features:
+            indexes.append(i)
+    assert ((np.delete(transformed, indexes, axis=1) == np.delete(X, indexes, axis=1)).all())
+    ncp = gen.ncp_
+    if len(expexted_generalizations['ranges'].keys()) > 0 or len(expexted_generalizations['categories'].keys()) > 0:
+        assert (ncp > 0)
+        assert (((transformed[indexes]) != (X[indexes])).any())
+
+
+def test_minimizer_fit_pandas_QI(data):
+    features = ['age', 'height', 'weight', 'sex', 'ola']
+    X = [[23, 165, 65, 'f', 'aa'],
+         [45, 158, 76, 'f', 'aa'],
+         [56, 123, 78, 'f', 'bb'],
+         [67, 154, 87, 'm', 'aa'],
+         [45, 149, 45, 'f', 'bb'],
+         [42, 166, 76, 'm', 'bb'],
+         [73, 172, 85, 'm', 'bb'],
+         [94, 168, 92, 'f', 'aa'],
+         [69, 175, 95, 'm', 'aa'],
+         [24, 181, 49, 'm', 'bb'],
+         [18, 190, 69, 'm', 'bb']]
+
+    y = [1, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0]
+    X = pd.DataFrame(X, columns=features)
+    QI = ['age', 'weight', 'ola']
+
+    numeric_features = ["age", "height", "weight"]
+    numeric_transformer = Pipeline(
+        steps=[('imputer', SimpleImputer(strategy='constant', fill_value=0))]
+    )
+
+    categorical_features = ["sex", "ola"]
+    categorical_transformer = OneHotEncoder(handle_unknown="ignore")
+
+    preprocessor = ColumnTransformer(
+        transformers=[
+            ("num", numeric_transformer, numeric_features),
+            ("cat", categorical_transformer, categorical_features),
+        ]
+    )
+    encoded = preprocessor.fit_transform(X)
+    base_est = DecisionTreeClassifier(random_state=0, min_samples_split=2,
+                                      min_samples_leaf=1)
+    base_est.fit(encoded, y)
+    predictions = base_est.predict(encoded)
+    # Append classifier to preprocessing pipeline.
+    # Now we have a full prediction pipeline.
+    gen = GeneralizeToRepresentative(base_est, features=features, target_accuracy=0.5,
+                                     categorical_features=categorical_features, features_to_minimize=QI)
+    gen.fit(X, predictions)
+    transformed = gen.transform(X)
+    gener = gen.generalizations_
+    expexted_generalizations = {'ranges': {'age': [], 'weight': [47.0]}, 'categories': {'ola': [['bb', 'aa']]},
+                                'untouched': ['height', 'sex']}
+
+    for key in expexted_generalizations['ranges']:
+        assert (set(expexted_generalizations['ranges'][key]) == set(gener['ranges'][key]))
+    for key in expexted_generalizations['categories']:
+        assert (set([frozenset(sl) for sl in expexted_generalizations['categories'][key]]) ==
+                set([frozenset(sl) for sl in gener['categories'][key]]))
+    assert (set(expexted_generalizations['untouched']) == set(gener['untouched']))
+    assert (transformed.drop(QI, axis=1).equals(X.drop(QI, axis=1)))
+
     modified_features = [f for f in features if
                          f in expexted_generalizations['categories'].keys() or f in expexted_generalizations[
                              'ranges'].keys()]
@@ -230,24 +323,27 @@ def test_minimizer_params_categorical(data):
 def test_minimize_ndarray_iris():
     features = ['sepal length (cm)', 'sepal width (cm)', 'petal length (cm)', 'petal width (cm)']
     (x_train, y_train), _ = get_iris_dataset()
+    QI = [0, 2]
     model = DecisionTreeClassifier(random_state=0, min_samples_split=2,
                                    min_samples_leaf=1)
     model.fit(x_train, y_train)
     pred = model.predict(x_train)
 
-    gen = GeneralizeToRepresentative(model, target_accuracy=0.7, features=features)
+    gen = GeneralizeToRepresentative(model, target_accuracy=0.3, features=features, features_to_minimize=QI)
     gen.fit(x_train, pred)
     transformed = gen.transform(x_train)
     gener = gen.generalizations_
-    expexted_generalizations = {
-        'ranges': {'sepal length (cm)': [5.0], 'sepal width (cm)': [], 'petal length (cm)': [4.950000047683716],
-                   'petal width (cm)': [0.800000011920929, 1.699999988079071]}, 'categories': {}, 'untouched': []}
+    expexted_generalizations = {'ranges': {'sepal length (cm)': [], 'petal length (cm)': [2.449999988079071]},
+                                'categories': {}, 'untouched': ['petal width (cm)', 'sepal width (cm)']}
+
     for key in expexted_generalizations['ranges']:
         assert (set(expexted_generalizations['ranges'][key]) == set(gener['ranges'][key]))
     for key in expexted_generalizations['categories']:
         assert (set([frozenset(sl) for sl in expexted_generalizations['categories'][key]]) ==
                 set([frozenset(sl) for sl in gener['categories'][key]]))
     assert (set(expexted_generalizations['untouched']) == set(gener['untouched']))
+    assert ((np.delete(transformed, QI, axis=1) == np.delete(x_train, QI, axis=1)).all())
+
     modified_features = [f for f in features if
                          f in expexted_generalizations['categories'].keys() or f in expexted_generalizations[
                              'ranges'].keys()]
@@ -262,70 +358,19 @@ def test_minimize_ndarray_iris():
         assert (((transformed[indexes]) != (x_train[indexes])).any())
 
 
-def test_minimize_pandas_nursery():
-    (x_train, y_train), _ = get_nursery_dataset()
-    x_train = x_train.astype(str)
-    x_train.reset_index(inplace=True, drop=True)
-    y_train.reset_index(inplace=True, drop=True)
-    QI = ["finance", "social", "health"]
-    features = ["parents", "has_nurs", "form", "children", "housing", "finance", "social", "health"]
-    categorical_features = ["parents", "has_nurs", "form", "housing", "finance", "social", "health", 'children']
-    numeric_features = [f for f in features if f not in categorical_features]
-    numeric_transformer = Pipeline(
-        steps=[('imputer', SimpleImputer(strategy='constant', fill_value=0))]
-    )
-    categorical_transformer = OneHotEncoder(handle_unknown="ignore", sparse=False)
-    preprocessor = ColumnTransformer(
-        transformers=[
-            ("num", numeric_transformer, numeric_features),
-            ("cat", categorical_transformer, categorical_features),
-        ]
-    )
-    encoded = preprocessor.fit_transform(x_train)
-    base_est = DecisionTreeClassifier(random_state=0, min_samples_split=2,
-                                      min_samples_leaf=1)
-    base_est.fit(encoded, y_train)
-    predictions = base_est.predict(encoded)
-
-    gen = GeneralizeToRepresentative(base_est, target_accuracy=0.8, features=features,
-                                     categorical_features=categorical_features)
-    gen.fit(x_train, predictions)
-    transformed = gen.transform(x_train)
-    gener = gen.generalizations_
-    expexted_generalizations = {'ranges': {}, 'categories': {'parents': [['great_pret', 'pretentious', 'usual']],
-                                                             'has_nurs': [['critical', 'less_proper', 'proper'],
-                                                                          ['very_crit'], ['improper']], 'form': [
-            ['foster', 'completed', 'complete', 'incomplete']], 'housing': [['convenient', 'less_conv', 'critical']],
-                                                             'finance': [['convenient', 'inconv']],
-                                                             'social': [['problematic', 'nonprob', 'slightly_prob']],
-                                                             'health': [['priority'], ['recommended'], ['not_recom']],
-                                                             'children': [['2', '3', '4', '1']]}, 'untouched': []}
-    for key in expexted_generalizations['ranges']:
-        assert (set(expexted_generalizations['ranges'][key]) == set(gener['ranges'][key]))
-    for key in expexted_generalizations['categories']:
-        assert (set([frozenset(sl) for sl in expexted_generalizations['categories'][key]]) ==
-                set([frozenset(sl) for sl in gener['categories'][key]]))
-    assert (set(expexted_generalizations['untouched']) == set(gener['untouched']))
-    modified_features = [f for f in features if
-                         f in expexted_generalizations['categories'].keys() or f in expexted_generalizations[
-                             'ranges'].keys()]
-    assert (transformed.drop(modified_features, axis=1).equals(x_train.drop(modified_features, axis=1)))
-    ncp = gen.ncp_
-    if len(expexted_generalizations['ranges'].keys()) > 0 or len(expexted_generalizations['categories'].keys()) > 0:
-        assert (ncp > 0)
-        assert (((transformed[modified_features]).equals(x_train[modified_features])) == False)
-
-
 def test_minimize_pandas_adult():
     (x_train, y_train), _ = get_adult_dataset()
-    x_train = x_train.head(5000)
-    y_train = y_train.head(5000)
+    x_train = x_train.head(1000)
+    y_train = y_train.head(1000)
 
     features = ['age', 'workclass', 'education-num', 'marital-status', 'occupation', 'relationship', 'race', 'sex',
                 'capital-gain', 'capital-loss', 'hours-per-week', 'native-country']
 
     categorical_features = ['workclass', 'marital-status', 'occupation', 'relationship', 'race', 'sex',
-                            'native-country']
+                            'hours-per-week', 'native-country']
+
+    QI = ['age', 'workclass', 'education-num', 'marital-status', 'occupation', 'relationship', 'race', 'sex',
+          'native-country']
 
     numeric_features = [f for f in features if f not in categorical_features]
     numeric_transformer = Pipeline(
@@ -344,33 +389,101 @@ def test_minimize_pandas_adult():
     base_est.fit(encoded, y_train)
     predictions = base_est.predict(encoded)
 
-    gen = GeneralizeToRepresentative(base_est, target_accuracy=0.8, features=features,
-                                     categorical_features=categorical_features)
+    gen = GeneralizeToRepresentative(base_est, target_accuracy=0.7, features=features,
+                                     categorical_features=categorical_features, features_to_minimize=QI)
     gen.fit(x_train, predictions)
     transformed = gen.transform(x_train)
     gener = gen.generalizations_
-    expexted_generalizations = {
-        'ranges': {'age': [20.0], 'education-num': [11.5, 12.5], 'capital-gain': [5095.5, 7139.5], 'capital-loss': [],
-                   'hours-per-week': []}, 'categories': {'workclass': [
-            ['Private', 'Without-pay', 'Self-emp-not-inc', '?', 'Federal-gov', 'Self-emp-inc', 'State-gov',
-             'Local-gov']], 'marital-status': [
-            ['Married-civ-spouse', 'Never-married', 'Widowed', 'Married-AF-spouse', 'Separated',
-             'Married-spouse-absent'], ['Divorced']], 'occupation': [
-            ['Transport-moving', 'Priv-house-serv', '?', 'Armed-Forces', 'Prof-specialty', 'Farming-fishing',
-             'Exec-managerial', 'Machine-op-inspct', 'Other-service', 'Sales', 'Protective-serv', 'Handlers-cleaners',
-             'Tech-support', 'Craft-repair', 'Adm-clerical']], 'relationship': [
-            ['Not-in-family', 'Own-child', 'Wife', 'Other-relative', 'Husband', 'Unmarried']], 'race': [
-            ['Other', 'Asian-Pac-Islander', 'Black', 'White', 'Amer-Indian-Eskimo']], 'sex': [['Male', 'Female']],
-            'native-country': [
-                ['LatinAmerica', 'Other', 'UnitedStates', 'SouthAmerica',
-                 'BritishCommonwealth', 'Euro_2', 'Unknown', 'China',
-                 'Euro_1', 'SE_Asia']]}, 'untouched': []}
+    expexted_generalizations = {'ranges': {'age': [], 'education-num': []}, 'categories': {
+        'workclass': [['Self-emp-not-inc', 'Private', 'Federal-gov', 'Self-emp-inc', '?', 'Local-gov', 'State-gov']],
+        'marital-status': [
+            ['Divorced', 'Married-AF-spouse', 'Married-spouse-absent', 'Widowed', 'Separated', 'Married-civ-spouse',
+             'Never-married']], 'occupation': [
+            ['Tech-support', 'Priv-house-serv', 'Machine-op-inspct', 'Other-service', 'Prof-specialty', 'Adm-clerical',
+             'Protective-serv', 'Handlers-cleaners', 'Transport-moving', 'Armed-Forces', '?', 'Sales',
+             'Farming-fishing', 'Exec-managerial', 'Craft-repair']],
+        'relationship': [['Not-in-family', 'Wife', 'Other-relative', 'Husband', 'Unmarried', 'Own-child']],
+        'race': [['Asian-Pac-Islander', 'White', 'Other', 'Black', 'Amer-Indian-Eskimo']], 'sex': [['Female', 'Male']],
+        'native-country': [
+            ['Euro_1', 'LatinAmerica', 'BritishCommonwealth', 'SouthAmerica', 'UnitedStates', 'China', 'Euro_2',
+             'SE_Asia', 'Other', 'Unknown']]}, 'untouched': ['capital-loss', 'hours-per-week', 'capital-gain']}
+
     for key in expexted_generalizations['ranges']:
         assert (set(expexted_generalizations['ranges'][key]) == set(gener['ranges'][key]))
     for key in expexted_generalizations['categories']:
         assert (set([frozenset(sl) for sl in expexted_generalizations['categories'][key]]) ==
                 set([frozenset(sl) for sl in gener['categories'][key]]))
     assert (set(expexted_generalizations['untouched']) == set(gener['untouched']))
+    assert (transformed.drop(QI, axis=1).equals(x_train.drop(QI, axis=1)))
+
+    modified_features = [f for f in features if
+                         f in expexted_generalizations['categories'].keys() or f in expexted_generalizations[
+                             'ranges'].keys()]
+    assert (transformed.drop(modified_features, axis=1).equals(x_train.drop(modified_features, axis=1)))
+    ncp = gen.ncp_
+    if len(expexted_generalizations['ranges'].keys()) > 0 or len(expexted_generalizations['categories'].keys()) > 0:
+        assert (ncp > 0)
+        assert (((transformed[modified_features]).equals(x_train[modified_features])) == False)
+
+
+def test_german_credit_pandas():
+    (x_train, y_train), (x_test, y_test) = get_german_credit_dataset()
+    features = ["Existing_checking_account", "Duration_in_month", "Credit_history", "Purpose", "Credit_amount",
+                "Savings_account", "Present_employment_since", "Installment_rate", "Personal_status_sex", "debtors",
+                "Present_residence", "Property", "Age", "Other_installment_plans", "Housing",
+                "Number_of_existing_credits", "Job", "N_people_being_liable_provide_maintenance", "Telephone",
+                "Foreign_worker"]
+    categorical_features = ["Existing_checking_account", "Credit_history", "Purpose", "Savings_account",
+                            "Present_employment_since", "Personal_status_sex", "debtors", "Property",
+                            "Other_installment_plans", "Housing", "Job"]
+    QI = ["Duration_in_month", "Credit_history", "Purpose", "debtors", "Property", "Other_installment_plans",
+          "Housing", "Job"]
+
+
+    numeric_features = [f for f in features if f not in categorical_features]
+    numeric_transformer = Pipeline(
+        steps=[('imputer', SimpleImputer(strategy='constant', fill_value=0))]
+    )
+    categorical_transformer = OneHotEncoder(handle_unknown="ignore", sparse=False)
+    preprocessor = ColumnTransformer(
+        transformers=[
+            ("num", numeric_transformer, numeric_features),
+            ("cat", categorical_transformer, categorical_features),
+        ]
+    )
+    encoded = preprocessor.fit_transform(x_train)
+    base_est = DecisionTreeClassifier(random_state=0, min_samples_split=2,
+                                      min_samples_leaf=1)
+    base_est.fit(encoded, y_train)
+    predictions = base_est.predict(encoded)
+
+    gen = GeneralizeToRepresentative(base_est, target_accuracy=0.7, features=features,
+                                     categorical_features=categorical_features, features_to_minimize=QI)
+    gen.fit(x_train, predictions)
+    transformed = gen.transform(x_train)
+    gener = gen.generalizations_
+    expexted_generalizations = {'ranges': {'Duration_in_month': [31.5]},
+                                'categories': {'Credit_history': [['A30', 'A32', 'A31', 'A34', 'A33']], 'Purpose': [
+                                    ['A41', 'A46', 'A43', 'A40', 'A44', 'A410', 'A49', 'A45', 'A48', 'A42']],
+                                               'debtors': [['A101', 'A102', 'A103']],
+                                               'Property': [['A124', 'A121', 'A122', 'A123']],
+                                               'Other_installment_plans': [['A142', 'A141', 'A143']],
+                                               'Housing': [['A151', 'A152', 'A153']],
+                                               'Job': [['A172', 'A171', 'A174', 'A173']]},
+                                'untouched': ['Installment_rate', 'Present_residence', 'Personal_status_sex',
+                                              'Foreign_worker', 'Telephone', 'Savings_account',
+                                              'Number_of_existing_credits', 'N_people_being_liable_provide_maintenance',
+                                              'Age', 'Existing_checking_account', 'Credit_amount',
+                                              'Present_employment_since']}
+
+    for key in expexted_generalizations['ranges']:
+        assert (set(expexted_generalizations['ranges'][key]) == set(gener['ranges'][key]))
+    for key in expexted_generalizations['categories']:
+        assert (set([frozenset(sl) for sl in expexted_generalizations['categories'][key]]) ==
+                set([frozenset(sl) for sl in gener['categories'][key]]))
+    assert (set(expexted_generalizations['untouched']) == set(gener['untouched']))
+    assert (transformed.drop(QI, axis=1).equals(x_train.drop(QI, axis=1)))
+
     modified_features = [f for f in features if
                          f in expexted_generalizations['categories'].keys() or f in expexted_generalizations[
                              'ranges'].keys()]