Benchmarks

Here we will demonstrate some benchmarks against some alternatives.

Data

UCI Credit card dataset with 30k rows and 23 features.

import pandas as pd
from skorecard.datasets import load_credit_card
from sklearn.model_selection import train_test_split

data = load_credit_card(as_frame=True)
print(f"data shape: {data.shape}")

X_train, X_test, y_train, y_test = train_test_split(
    data.drop(["y"], axis=1), data[["y"]], test_size=0.25, random_state=42
)

data_train_opt, data_test_opt = train_test_split(data, test_size=0.25, random_state=42)

data shape: (30000, 24)

Experiment setup

from sklearn.metrics import roc_auc_score


def report_auc(clf, X_train, y_train, X_test, y_test):
    proba_train = clf.predict_proba(X_train)[:, 1]
    proba_test = clf.predict_proba(X_test)[:, 1]

    auc_train = round(roc_auc_score(y_train, proba_train), 4)
    auc_test = round(roc_auc_score(y_test, proba_test), 4)

    return auc_train, auc_test

from memo import memlist, time_taken

data = []


@memlist(data=data)
@time_taken()
def fit_eval_record(clf, name, opt=False):
    if opt:
        clf.fit(data_train_opt)
        proba_train = clf.predict_proba(data_train_opt)[:, 1]
        proba_test = clf.predict_proba(data_test_opt)[:, 1]

        auc_train = round(roc_auc_score(y_train, proba_train), 4)
        auc_test = round(roc_auc_score(y_test, proba_test), 4)

    else:
        clf.fit(X_train, y_train)
        auc_train, auc_test = report_auc(clf, X_train, y_train, X_test, y_test)

    return {"auc_train": auc_train, "auc_test": auc_test}

Baseline

from skorecard import Skorecard

scorecard = Skorecard()
fit_eval_record(scorecard, name="skorecard.Scorecard")

{'auc_train': 0.7727, 'auc_test': 0.766, 'time_taken': 16.73}

# from sklearn.pipeline import make_pipeline
# from sklearn.linear_model import LogisticRegression
# from skorecard.preprocessing import WoeEncoder
# from skorecard.bucketers import DecisionTreeBucketer, OptimalBucketer
# from category_encoders.woe import WOEEncoder

# pipe = make_pipeline(
#     DecisionTreeBucketer(),
#     OptimalBucketer(),
#     #WoeEncoder(),
#     WOEEncoder(cols=X_train.columns),
#     LogisticRegression(solver="lbfgs", max_iter=400)
# )

# fit_eval_record(pipe, name="pipeline")

# # .7166 with skorecard woe in 3.7s
# # 0.758 with no WOE in 3.9s
# # 0.7661 with WOE on all cols.

Optbinning

See the excellent package Optbinning.

from optbinning import BinningProcess
from optbinning import Scorecard
from sklearn.linear_model import LogisticRegression
import pandas as pd

selection_criteria = {"iv": {"min": 0.02, "max": 1}, "quality_score": {"min": 0.01}}
binning_process = BinningProcess(variable_names=list(X_train.columns), selection_criteria=selection_criteria)

estimator = LogisticRegression(solver="lbfgs")

opt_scorecard = Scorecard(
    target="y",
    binning_process=binning_process,
    estimator=estimator,
    scaling_method="min_max",
    scaling_method_params={"min": 300, "max": 850},
)

opt_scorecard.fit(data_train_opt)
fit_eval_record(opt_scorecard, name="optbinning.Scorecard", opt=True)

{'auc_train': 0.7719, 'auc_test': 0.7628, 'time_taken': 1.88}

Basic LR

from sklearn.linear_model import LogisticRegression
from sklearn.preprocessing import StandardScaler
from sklearn.pipeline import make_pipeline

pipe = make_pipeline(StandardScaler(), LogisticRegression(random_state=42, solver="lbfgs"))

fit_eval_record(pipe, name="sklearn.LogisticRegression")

/Users/iv58uq/miniconda3/envs/dancard_py37/lib/python3.7/site-packages/sklearn/utils/validation.py:63: DataConversionWarning: A column-vector y was passed when a 1d array was expected. Please change the shape of y to (n_samples, ), for example using ravel().
  return f(*args, **kwargs)

{'auc_train': 0.724, 'auc_test': 0.7232, 'time_taken': 0.11}

LightGBM model

The LightGBM Classifier documentation can be found here

from lightgbm import LGBMClassifier

clf = LGBMClassifier(random_state=42, max_depth=10, learning_rate=0.01)

fit_eval_record(clf, name="LightGBM")

/Users/iv58uq/miniconda3/envs/dancard_py37/lib/python3.7/site-packages/sklearn/utils/validation.py:63: DataConversionWarning: A column-vector y was passed when a 1d array was expected. Please change the shape of y to (n_samples, ), for example using ravel().
  return f(*args, **kwargs)

{'auc_train': 0.8038, 'auc_test': 0.7778, 'time_taken': 0.33}

Results

pd.DataFrame(data).sort_values("auc_test", ascending=False).drop("opt", axis=1)

	name	auc_train	auc_test	time_taken
3	LightGBM	0.8038	0.7778	0.33
0	skorecard.Scorecard	0.7727	0.7660	16.73
1	optbinning.Scorecard	0.7719	0.7628	1.88
2	sklearn.LogisticRegression	0.7240	0.7232	0.11