loan risk predictor models and to assist the financial institutions to manage creditworthiness and loan default
risks.
1.1 Literature review
Risk assessment on loans has always been a major concern in the field of banking and finance for many years
with many papers directed toward enhancing the accuracy of the models utilizing statistical methodology
alongside artificial neural networks and other intelligent methodologies. This section discusses a historical
perspective of loan risk prediction models with ANNs and various architectures discussion.
Speaking of the methods applied earlier for loan risk prediction, it is possible to mention logistic regression,
decision trees, and discriminant analysis. According to Thomas et al., logistic regression was appropriate in this
study because it is simple and easily interpretable.
[3]
These models presume the straight-line relationship between borrower characteristics and loan performance,
while the actual data can be different. It was Z-score model, used for corporate bankruptcy
prediction, that provided groundwork for credit risk evaluation. However, traditional models are applied to
discrete variables as linear and independent; therefore, they cannot help much when analyzing interdependent
and nonlinear data of financial fields.
[4]
By the help of evolved machine learning, random forests, decision trees, gradient boosting machines (GBMs)
and, support vector machines (SVMs) were commonly used in predictive modeling. Malhotra and Malhotra and
Lessmann et al. established that self-regulating algorithms offered superior performance to conventional
methods in dealing with vast databases that include complicated feature interactions.
[5,6]
But deep learning has
opened up new ways in dealing with non-linear relationship of loan risks prediction. Kou et al. offered an
extensive analysis; they showed how, despite the numerous choices available, deep learning models, and ANNs
predominantly, efficiently identify even subtle relationships in the financial data. Unlike conventional
approaches, these models do not entail feature engineering often needed for popular algorithms and can
learn from data directly through multiple transformations.
[7]
Because of the non-linear mapping capability of ANN, between the input and target variable, the application of
ANNs has shown promising results in loan risk prediction. Zhang and Kanda employed a simple feedforward
ANN for credit defaults with only one hidden layer including better accurate predicting as compared to logistic
regression models. But as they pointed out, they realized how delicate the model performance might be with
network architecture concerning the number of hidden nodes and layers.
[8]
In their study, Heaton et al.
showed that Deep ANNs are capable of analyzing a large volume of values making them appropriate for
analytical use in the financial sector. But the study also highlighted some of the disadvantages which include
over fitting especially with deeper networks architectures.
[9]
Goodfellow et al., reiterated the argument of depth
when addressing the effectiveness of the network stating that while deeper networks provide better solutions,
they will also lead to greater chances of overfitting and could be very computation intensive.
[10]
ANN is ideally best suited and the overall count of hidden layers and neural units has been a subject to extensive
research. Another downside of deeper networks for Hinton et al. and LeCun et al. these models enable
sophisticated performances to be learned due to their efficiency but are computationally intensive and more
sensitive to overfitting if training data is scarce.
[11,12]
Peng, Kou and Zhou discuss how the magnitude of the
systems with more hidden layers fared better than the shallow ones, though more care had to be taken to
avoid overfitting than through regularization techniques including dropout and batch normalization. Another
work by Chaudhary et al. focused on the impacts of different layer ANNs on the credit scoring and discovered
rising the depth of the network helped enhancing the precision of the model but added extra training
difficulty.
[13,14]
The literature review also attests to the point of feature selection and the study of effects of different risk
factors. In their study on credit scoring using logistic regression T. Hastie, R Tibshiran, and J Friedman found
predictors including credit history, income, and employment. The findings have revealed that these risk factors
are significant and are persistent contributing factors to loan default predictions.
[15]
Subsequently, Kou et al.
further developed this by using deep learning methods to investigate the effect of the aforementioned risk
factors in non-linear models. They found out that deep ANNs contain the ability to reveal the behavior
between borrower characteristics and default rates undetectable by conventional models.
[7]
Various variants of ANNs have been assessed in several comparative researches to determine their impact on
model performance. Yu et al. worked on the comparison of shallow and deep ANNs for loan default prediction
and discovered that the loan default predicting power of deeper networks is superior as well as is the