Building a Lead Scoring Model with EvalML

In this demo, we will build an optimized lead scoring model using EvalML. To optimize the pipeline, we will set up an objective function to maximize the revenue generated with true positives while taking into account the cost of false positives. At the end of this demo, we also show you how introducing the right objective during the training is over 6x better than using a generic machine learning metric like AUC.

[1]:
import evalml
from evalml import AutoMLSearch
from evalml.objectives import LeadScoring

Configure LeadScoring

To optimize the pipelines toward the specific business needs of this model, you can set your own assumptions for how much value is gained through true positives and the cost associated with false positives. These parameters are

  • true_positive - dollar amount to be gained with a successful lead

  • false_positive - dollar amount to be lost with an unsuccessful lead

Using these parameters, EvalML builds a pileline that will maximize the amount of revenue per lead generated.

[2]:
lead_scoring_objective = LeadScoring(
    true_positives=1000,
    false_positives=-10
)

Dataset

We will be utilizing a dataset detailing a customer’s job, country, state, zip, online action, the dollar amount of that action and whether they were a successful lead.

[3]:
from urllib.request import urlopen
import pandas as pd
import woodwork as ww
customers_data = urlopen('https://featurelabs-static.s3.amazonaws.com/lead_scoring_ml_apps/customers.csv')
interactions_data = urlopen('https://featurelabs-static.s3.amazonaws.com/lead_scoring_ml_apps/interactions.csv')
leads_data = urlopen('https://featurelabs-static.s3.amazonaws.com/lead_scoring_ml_apps/previous_leads.csv')
customers = pd.read_csv(customers_data)
interactions = pd.read_csv(interactions_data)
leads = pd.read_csv(leads_data)

X = customers.merge(interactions, on='customer_id').merge(leads, on='customer_id')
y = X['label']
X = X.drop(['customer_id', 'date_registered', 'birthday','phone', 'email',
            'owner', 'company', 'id', 'time_x',
            'session', 'referrer', 'time_y', 'label', 'country'], axis=1)
display(X.head())
job state zip action amount
0 Engineer, mining NY 60091.0 page_view NaN
1 Psychologist, forensic CA NaN purchase 135.23
2 Psychologist, forensic CA NaN page_view NaN
3 Air cabin crew NaN 60091.0 download NaN
4 Air cabin crew NaN 60091.0 page_view NaN

We will convert our data into Woodwork data structures. Doing so enables us to have more control over the types passed to and inferred by AutoML.

[4]:
X = ww.DataTable(X, semantic_tags={'job': 'category'}, logical_types={'job': 'Categorical'})
y = ww.DataColumn(y)
X.types
[4]:
Physical Type Logical Type Semantic Tag(s)
Data Column
job category Categorical ['category']
state category Categorical ['category']
zip float64 Double ['numeric']
action category Categorical ['category']
amount float64 Double ['numeric']

Search for the best pipeline

In order to validate the results of the pipeline creation and optimization process, we will save some of our data as a holdout set.

EvalML natively supports one-hot encoding and imputation so the above NaN and categorical values will be taken care of.

[5]:
X_train, X_holdout, y_train, y_holdout = evalml.preprocessing.split_data(X, y, problem_type='binary', test_size=0.2, random_seed=0)

print(X.types)
            Physical Type Logical Type Semantic Tag(s)
Data Column
job              category  Categorical    ['category']
state            category  Categorical    ['category']
zip               float64       Double     ['numeric']
action           category  Categorical    ['category']
amount            float64       Double     ['numeric']

Because the lead scoring labels are binary, we will use AutoMLSearch(X_train=X_train, y_train=y_train, problem_type='binary'). When we call .search(), the search for the best pipeline will begin.

[6]:
automl = AutoMLSearch(X_train=X_train, y_train=y_train,
                      problem_type='binary',
                      objective=lead_scoring_objective,
                      additional_objectives=['auc'],
                      max_batches=1,
                      optimize_thresholds=True)

automl.search()
Generating pipelines to search over...
The following labels fall below 10% of the target: [True]
*****************************
* Beginning pipeline search *
*****************************

Optimizing for Lead Scoring.
Greater score is better.

Using SequentialEngine to train and score pipelines.
Searching up to 1 batches for a total of 9 pipelines.
Allowed model families: xgboost, extra_trees, lightgbm, catboost, linear_model, decision_tree, random_forest

Batch 1: (1/9) Mode Baseline Binary Classification P... Elapsed:00:00
        Starting cross validation
        Finished cross validation - mean Lead Scoring: 0.000
Batch 1: (2/9) Decision Tree Classifier w/ Imputer +... Elapsed:00:01
        Starting cross validation
        Finished cross validation - mean Lead Scoring: 14.821
Batch 1: (3/9) LightGBM Classifier w/ Imputer + One ... Elapsed:00:03
        Starting cross validation
        Finished cross validation - mean Lead Scoring: 13.354
Batch 1: (4/9) Extra Trees Classifier w/ Imputer + O... Elapsed:00:05
        Starting cross validation
        Finished cross validation - mean Lead Scoring: 15.294
Batch 1: (5/9) Elastic Net Classifier w/ Imputer + O... Elapsed:00:07
        Starting cross validation
        Finished cross validation - mean Lead Scoring: 15.997
Batch 1: (6/9) CatBoost Classifier w/ Imputer           Elapsed:00:09
        Starting cross validation
        Finished cross validation - mean Lead Scoring: 15.997
Batch 1: (7/9) XGBoost Classifier w/ Imputer + One H... Elapsed:00:10
        Starting cross validation
        Finished cross validation - mean Lead Scoring: 14.537
Batch 1: (8/9) Random Forest Classifier w/ Imputer +... Elapsed:00:12
        Starting cross validation
        Finished cross validation - mean Lead Scoring: 14.515
Batch 1: (9/9) Logistic Regression Classifier w/ Imp... Elapsed:00:14
        Starting cross validation
        Finished cross validation - mean Lead Scoring: 14.941

Search finished after 00:17
Best pipeline: Elastic Net Classifier w/ Imputer + One Hot Encoder + Standard Scaler
Best pipeline Lead Scoring: 15.996914

View rankings and select pipeline

Once the fitting process is done, we can see all of the pipelines that were searched, ranked by their score on the lead scoring objective we defined.

[7]:
automl.rankings
[7]:
id pipeline_name score validation_score percent_better_than_baseline high_variance_cv parameters
0 4 Elastic Net Classifier w/ Imputer + One Hot En... 15.996914 16.741935 inf False {'Imputer': {'categorical_impute_strategy': 'm...
1 5 CatBoost Classifier w/ Imputer 15.996914 16.741935 inf False {'Imputer': {'categorical_impute_strategy': 'm...
2 3 Extra Trees Classifier w/ Imputer + One Hot En... 15.293603 14.877419 inf False {'Imputer': {'categorical_impute_strategy': 'm...
3 8 Logistic Regression Classifier w/ Imputer + On... 14.940900 13.929032 inf False {'Imputer': {'categorical_impute_strategy': 'm...
4 1 Decision Tree Classifier w/ Imputer + One Hot ... 14.820570 16.741935 inf False {'Imputer': {'categorical_impute_strategy': 'm...
5 6 XGBoost Classifier w/ Imputer + One Hot Encoder 14.536504 15.541935 inf False {'Imputer': {'categorical_impute_strategy': 'm...
6 7 Random Forest Classifier w/ Imputer + One Hot ... 14.514975 14.948387 inf False {'Imputer': {'categorical_impute_strategy': 'm...
7 2 LightGBM Classifier w/ Imputer + One Hot Encoder 13.353574 14.400000 inf False {'Imputer': {'categorical_impute_strategy': 'm...
8 0 Mode Baseline Binary Classification Pipeline 0.000000 0.000000 0.0 False {'Baseline Classifier': {'strategy': 'mode'}}

To select the best pipeline we can call automl.best_pipeline.

[8]:
best_pipeline = automl.best_pipeline

Describe pipeline

You can get more details about any pipeline, including how it performed on other objective functions by calling .describe_pipeline() and specifying the id of the pipeline.

[9]:
automl.describe_pipeline(automl.rankings.iloc[0]["id"])
*************************************************************************
* Elastic Net Classifier w/ Imputer + One Hot Encoder + Standard Scaler *
*************************************************************************

Problem Type: binary
Model Family: Linear

Pipeline Steps
==============
1. Imputer
         * categorical_impute_strategy : most_frequent
         * numeric_impute_strategy : mean
         * categorical_fill_value : None
         * numeric_fill_value : None
2. One Hot Encoder
         * top_n : 10
         * features_to_encode : None
         * categories : None
         * drop : None
         * handle_unknown : ignore
         * handle_missing : error
3. Standard Scaler
4. Elastic Net Classifier
         * alpha : 0.5
         * l1_ratio : 0.5
         * n_jobs : -1
         * max_iter : 1000
         * penalty : elasticnet
         * loss : log

Training
========
Training for binary problems.
Objective to optimize binary classification pipeline thresholds for: <evalml.objectives.lead_scoring.LeadScoring object at 0x7f5cdc211ca0>
Total training time (including CV): 2.1 seconds

Cross Validation
----------------
             Lead Scoring   AUC # Training # Validation
0                  16.742 0.500   2479.000     1550.000
1                  15.600 0.500   2479.000     1550.000
2                  15.649 0.500   2480.000     1549.000
mean               15.997 0.500          -            -
std                 0.646 0.000          -            -
coef of var         0.040 0.000          -            -

Evaluate on hold out

Finally, since the best pipeline was trained on all of the training data, we evaluate it on the holdout dataset.

[10]:
best_pipeline.score(X_holdout, y_holdout, objectives=["auc", lead_scoring_objective])
[10]:
OrderedDict([('AUC', 0.5), ('Lead Scoring', 15.382631126397248)])

Why optimize for a problem-specific objective?

To demonstrate the importance of optimizing for the right objective, let’s search for another pipeline using AUC, a common machine learning metric. After that, we will score the holdout data using the lead scoring objective to see how the best pipelines compare.

[11]:
automl_auc = evalml.AutoMLSearch(X_train=X_train, y_train=y_train,
                                 problem_type='binary',
                                 objective='auc',
                                 additional_objectives=[],
                                 max_batches=1,
                                 optimize_thresholds=True)

automl_auc.search()
Generating pipelines to search over...
The following labels fall below 10% of the target: [True]
*****************************
* Beginning pipeline search *
*****************************

Optimizing for AUC.
Greater score is better.

Using SequentialEngine to train and score pipelines.
Searching up to 1 batches for a total of 9 pipelines.
Allowed model families: xgboost, extra_trees, lightgbm, catboost, linear_model, decision_tree, random_forest

Batch 1: (1/9) Mode Baseline Binary Classification P... Elapsed:00:00
        Starting cross validation
        Finished cross validation - mean AUC: 0.500
Batch 1: (2/9) Decision Tree Classifier w/ Imputer +... Elapsed:00:00
        Starting cross validation
        Finished cross validation - mean AUC: 0.594
Batch 1: (3/9) LightGBM Classifier w/ Imputer + One ... Elapsed:00:00
        Starting cross validation
        Finished cross validation - mean AUC: 0.671
Batch 1: (4/9) Extra Trees Classifier w/ Imputer + O... Elapsed:00:01
        Starting cross validation
        Finished cross validation - mean AUC: 0.689
Batch 1: (5/9) Elastic Net Classifier w/ Imputer + O... Elapsed:00:02
        Starting cross validation
        Finished cross validation - mean AUC: 0.500
Batch 1: (6/9) CatBoost Classifier w/ Imputer           Elapsed:00:02
        Starting cross validation
        Finished cross validation - mean AUC: 0.542
Batch 1: (7/9) XGBoost Classifier w/ Imputer + One H... Elapsed:00:03
        Starting cross validation
        Finished cross validation - mean AUC: 0.701
Batch 1: (8/9) Random Forest Classifier w/ Imputer +... Elapsed:00:04
        Starting cross validation
        Finished cross validation - mean AUC: 0.682
Batch 1: (9/9) Logistic Regression Classifier w/ Imp... Elapsed:00:05
        Starting cross validation
        Finished cross validation - mean AUC: 0.681

Search finished after 00:06
Best pipeline: XGBoost Classifier w/ Imputer + One Hot Encoder
Best pipeline AUC: 0.701032
[12]:
automl_auc.rankings
[12]:
id pipeline_name score validation_score percent_better_than_baseline high_variance_cv parameters
0 6 XGBoost Classifier w/ Imputer + One Hot Encoder 0.701032 0.720642 20.103249 False {'Imputer': {'categorical_impute_strategy': 'm...
1 3 Extra Trees Classifier w/ Imputer + One Hot En... 0.689375 0.727598 18.937464 False {'Imputer': {'categorical_impute_strategy': 'm...
2 7 Random Forest Classifier w/ Imputer + One Hot ... 0.682025 0.732789 18.202538 False {'Imputer': {'categorical_impute_strategy': 'm...
3 8 Logistic Regression Classifier w/ Imputer + On... 0.680782 0.696611 18.078176 False {'Imputer': {'categorical_impute_strategy': 'm...
4 2 LightGBM Classifier w/ Imputer + One Hot Encoder 0.671060 0.698287 17.105985 False {'Imputer': {'categorical_impute_strategy': 'm...
5 1 Decision Tree Classifier w/ Imputer + One Hot ... 0.594215 0.601705 9.421468 False {'Imputer': {'categorical_impute_strategy': 'm...
6 5 CatBoost Classifier w/ Imputer 0.542394 0.505055 4.239420 False {'Imputer': {'categorical_impute_strategy': 'm...
7 0 Mode Baseline Binary Classification Pipeline 0.500000 0.500000 0.000000 False {'Baseline Classifier': {'strategy': 'mode'}}
8 4 Elastic Net Classifier w/ Imputer + One Hot En... 0.500000 0.500000 0.000000 False {'Imputer': {'categorical_impute_strategy': 'm...

Like before, we can look at the rankings and pick the best pipeline.

[13]:
best_pipeline_auc = automl_auc.best_pipeline
[14]:
# get the auc and lead scoring score on holdout data
best_pipeline_auc.score(X_holdout, y_holdout,  objectives=["auc", lead_scoring_objective])
[14]:
OrderedDict([('AUC', 0.6662964641885766),
             ('Lead Scoring', -0.008598452278589854)])

When we optimize for AUC, we can see that the AUC score from this pipeline is better than the AUC score from the pipeline optimized for lead scoring. However, the revenue per lead gained was only $7 per lead when optimized for AUC and was $45 when optimized for lead scoring. As a result, we would gain up to 6x the amount of revenue if we optimized for lead scoring.

This happens because optimizing for AUC does not take into account the user-specified true_positive (dollar amount to be gained with a successful lead) and false_positive (dollar amount to be lost with an unsuccessful lead) values. Thus, the best pipelines may produce the highest AUC but may not actually generate the most revenue through lead scoring.

This example highlights how performance in the real world can diverge greatly from machine learning metrics.