Deep Learning vs Machine Learning Challenger Models for Default Risk with Explainability

This post details the credit default risk prediction with deep learning and machine learning models.

Overview

This article explores the comparison between deep learning and machine learning models for predicting default risk, emphasizing the importance of explainability in model predictions. It highlights the use of GPU acceleration to enhance performance and efficiency in processing large datasets, particularly in the context of mortgage delinquency predictions.

What You'll Learn

1

How to leverage GPU acceleration for model training and explainability

2

Why explainability is crucial in financial modeling and how to implement it using SHAP

3

How to use the NVTabular library to optimize data loading for PyTorch models

Prerequisites & Requirements

  • Understanding of machine learning and deep learning concepts
  • Familiarity with RAPIDS and PyTorch libraries(optional)

Key Questions Answered

What are challenger models in the context of default risk prediction?
Challenger models are competing models used to evaluate and improve the accuracy of predictions related to default risk. They help in assessing which model performs better in predicting outcomes like mortgage delinquencies, allowing data scientists to choose the most effective approach for their specific datasets.
How does GPU acceleration improve model training times?
GPU acceleration significantly reduces the training times for machine learning and deep learning models. For instance, the article reports a 29-fold speedup in computing Shap values when using GPU acceleration, which enhances the efficiency of model development and iteration.
What is the expected loss formula in financial modeling?
The expected loss (EL) is calculated using the formula EL = PD x LGD x EAD, where PD is the probability of default, LGD is the loss given default, and EAD is the exposure at default. This formula helps in quantifying the risk associated with loan defaults.
What advantages does NVTabular provide for PyTorch training?
NVTabular offers significant performance improvements for PyTorch training, achieving up to 6-fold faster run times compared to traditional data loading methods. This optimization is crucial for efficiently handling large datasets in deep learning applications.

Key Statistics & Figures

Speedup in computing Shap values
29-fold
Achieved through GPU acceleration during model training.
Percentage of loans that are delinquent in the dataset
approximately 4%
Indicates the imbalanced nature of the mortgage loan dataset used for modeling.
Total number of mortgages in the dataset
11.2 million
Used for training and testing the models discussed in the article.

Technologies & Tools

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Software
Rapids
Used for GPU-accelerated data science workflows.
Machine Learning Library
Xgboost
Implemented for predicting loan delinquencies.
Deep Learning Framework
Pytorch
Utilized for building and training deep learning models.
Data Processing Library
Nvtabular
Used for efficient data loading and preprocessing in deep learning applications.
Explainability Tool
Shap
Used for computing Shapley values to explain model predictions.
Explainability Tool
Captum
Used for calculating Shapley values in PyTorch models.

Key Actionable Insights

1
Utilize GPU acceleration to enhance the performance of machine learning models, especially when working with large datasets.
GPU acceleration can drastically reduce training times and improve the efficiency of model iterations, making it essential for data scientists and machine learning engineers to integrate into their workflows.
2
Implement SHAP values for model explainability to meet regulatory requirements and improve stakeholder trust.
By providing clear explanations for model predictions, organizations can enhance transparency and accountability, which is particularly important in financial services.
3
Leverage NVTabular for data preprocessing to streamline the training process of deep learning models.
Using NVTabular can significantly reduce data loading times, allowing for faster iterations and more efficient training cycles, which is critical in production environments.

Common Pitfalls

1
Neglecting the importance of explainability in machine learning models can lead to regulatory issues and loss of stakeholder trust.
Without clear explanations for model predictions, organizations may face challenges in justifying their decisions, especially in regulated industries like finance.
2
Overlooking the benefits of GPU acceleration can result in inefficient model training processes.
Failing to utilize available GPU resources may lead to longer training times and hinder the ability to iterate quickly on model improvements.

Related Concepts

Machine Learning
Deep Learning
Model Explainability
GPU Acceleration