dualPredictor 0.0.5

A Python package for simultaneous regression and binary classification for educational analytics.

dualPredictor

by D

dualPredictor is a Python package that can provide simultaneous regression and binary classification results for tabular datasets.

• Simultaneous Predictions: A model that perform regression and binary classification tasks simultaneously
• Regressor Selection (choose one): Choose from Lasso, Ridge, or LinearRegression(OLS) as the base regression model.
• Dynamic Cutoff Tuning metrics (choose one): Automatically tunes the cutoff value to maximize the Youden index, F1, or F2 score. Users can choose a metrics type.

1. Youden Index (J)

https://miro.medium.com/v2/resize:fit:842/1*LVilqC3cy4AgyC1wD4RH-A.png

$$J= Recall + Specificity - 1$$ J is a measure of the overall performance of a binary classifier. It is calculated as the sum of the recall and specificity minus 1. A high J statistic indicates that the classifier performs well on positive and negative cases.

• Recall measures a classifier's ability to identify positive cases correctly. A high recall means that the classifier is avoiding miss detects.
• Specificity measures the ability of a classifier to identify negative cases correctly. A high specificity means that the classifier is avoiding false alarms.

2. F scores (Option F1, F2 in Package)

$$F1 = 2 \cdot \frac{precision \cdot recall}{precision + recall}$$

F1 score is another measure of the overall performance of a binary classifier. It is calculated as the harmonic mean of the precision and recall. A high F1 score indicates that the classifier is performing well on both positive and negative cases.

$$F_\beta = (1 + \beta^2) \cdot \frac{precision \cdot recall}{\beta^2 \cdot precision + recall}$$ F-score with factor beta is a generalization of the F1 score that allows for different weights to be given to precision and recall. A beta value less than 1 indicates that the F-score is prone to precision, while a beta value greater than 1 indicates that the F-score is prone to recall.

In educational settings

In educational settings, avoiding miss detects (i.e., failing to identify at-risk students) is important. However, it is also important to avoid false alarms (i.e., identifying students as at-risk when they are not). Therefore, using a measure prone to recall is often desirable, such as the F1 score with beta > 1. Youden's J statistic and the F1 score are both measures that balance the avoidance of miss detects and the avoidance of false alarms. However, Youden's J statistic is less sensitive to false alarms (Specificity is less sensitive to false alarms compared to Precision) than the F1 score.

Installation

Install dualPredictor directly from PyPI using pip:

pip install dualPredictor

Dependencies dualPredictor requires:

• numpy
• scikit-learn
• matplotlib
• seaborn

DualModel

The DualModel class is a custom regressor that combines a base regression model (lasso, ridge, or OLS) with a dual classification approach. It allows for tuning an optimal cut-off value to classify samples into two classes based on the predicted regression values.

Parameters

• model_type (str, default='lasso'): The base regression model to use. Supported options are 'lasso', 'ridge', and 'ols' (Ordinary Least Squares).

• metric (str, default='youden_index'): The metric used to tune the optimal cut-off value. Supported options are 'f1_score', 'f2_score', and 'youden_index'.

• default_cut_off (float, default=0.5): The default cut-off value used to create binary labels. Samples with regression values below the cut-off are labeled as 0, and samples above or equal to the cut-off are labeled as 1.

Methods

• fit(X, y): Fit the DualModel to the training data.

  • Parameters:

    • X (array-like of shape (n_samples, n_features)): The input training data.
    • y (array-like of shape (n_samples,)): The target values.

  • Returns:

    • self: Fitted DualModel instance.

• predict(X): Predict the input data's regression values and binary classifications.

  • Parameters:

    • X (array-like of shape (n_samples, n_features)): The input data for prediction.

  • Returns:

    • grade_predictions (array-like of shape (n_samples,)): The predicted regression values.
    • class_predictions (array-like of shape (n_samples,)): The predicted binary classifications based on the optimal cut-off.

Attributes

• alpha_: The alpha value of the model. This value is only available if the model is a Lasso or Ridge regression model. (OLS do not have alpha)
• coef_: The coefficients of the model.
• intercept_: The intercept of the model.
• feature_names_in_: The names of the features used to train the model.
• optimal_cut_off: The optimal cut-off value determined by the specified metric.
• y_label_true_: The true binary labels are generated using the default cut-off value.

Example

# Import the DualModel class
from dual_model import DualModel

# Initializing and fitting the DualModel
# 'ols' for Ordinary Least Squares, a default cut-off value is provided
# The metric parameter specifies the method to tune the optimal cut-off
dual_clf = DualModel(model_type='ols', metric='youden_index', default_cut_off=1)
dual_clf.fit(X, y)

# Accessing the true binary labels generated based on the default cut-off
y_label_true = dual_clf.y_label_true_

# Retrieving the optimal cut-off value tuned based on the Youden Index
optimal_cut_off = dual_clf.optimal_cut_off

# Predicting grades (y_pred) and binary classification (at-risk or not) based on the optimal cut-off (y_label_pred)
y_pred, y_label_pred = dual_clf.predict(X)

Exmaples of Model Performances Plot

# Visualizations
# Plotting the actual vs. predicted values to assess regression performance
scatter_plot_fig = plot_scatter(y_pred, y)

# Plotting the confusion matrix to evaluate binary classification performance
cm_plot = plot_cm(y_label_true, y_label_pred)

# Plotting the non-zero coefficients of the regression model to interpret feature importance
feature_plot = plot_feature_coefficients(coef=dual_clf.coef_, feature_names=dual_clf.feature_names_in_)

References:

• Youden's J statistic - Wikipedia
• F-score - Wikipedia
• Scikit-learn - Model Evaluation