How to assess a good logistic model?

A logistic model is a statistical framework for predicting the probability of an occurrence. These models are commonly used in industries including banking, healthcare, and marketing to assist with important business decisions. These models must be precise and reliable since the results reached from them can greatly affect how a project or business will end.

It is essential to assess the model's quality to ensure that the predictions offered by a logistic model are trustworthy. Numerous metrics and techniques can be employed to determine a logistic model's accuracy and dependability. By properly analyzing a logistic model, businesses and academics can base their decisions more wisely on the predictions it makes. This article will discuss how to evaluate a robust logistic model.

Assessing a good logistic model


One of the most crucial variables for assessing a logistic model is accuracy. It counts how many of the model's predictions on the test set were accurate. An accurate logistic model should be at least 80%.

It is impossible to overestimate the value of excellent accuracy in logistic models. Important business choices are made using logistic models, and the model's predictions can have a big influence on how a firm or research endeavor turns out. Poor accuracy in a model indicates that the predictions it makes are unreliable and untrustworthy. This could result in faulty judgment, which might have detrimental effects on the enterprise or research endeavor.

To calculate accuracy, you can use the following formula − (True Positives + True Negatives) / (True Positives + True Negatives + False Positives + False Negatives).

Recall and Precision

Two crucial measures for assessing a logistic model are recall and precision. Both assess how well the model can identify instances of the desired class and categorize them appropriately. But they go about it in various ways.

Out of all positive forecasts, precision is the proportion of accurate positive predictions. It assesses the model's capacity to properly detect positive occurrences while minimizing the number of false positives. High precision means that when the model detects a positive occurrence, it does so with few false positives and makes accurate predictions.

On the other hand, recall is the proportion of accurate positive forecasts among all real positive cases. It evaluates how well the model can find every positive occurrence while avoiding overly many false negatives. A high recall means that the model is correctly detecting the majority of positive events while not overly missing others.

In logistic models, it's crucial to strike a compromise between recall and precision. High accuracy without high recall might result in a model that is overly cautious and won't catch all occurrences of positivity. On the other side, a model that is excessively liberal and produces a lot of false positives might result from high recall without high accuracy. Precision and recall should be balanced in a good logistic model.

You can use the formulae Precision = (True Positives) / (True Positives + False Positives) and Recall = (True Positives) / (True Positives + False Negatives) to determine precision and recall.

Confusion Matrix

The effectiveness of a logistic model is assessed using a confusion matrix, which is a table. It is an effective tool for comprehending the true positive, false positive, true negative, and false negative predictions provided by the model. The confusion matrix provides a quick and simple approach to assess the model's performance and the harmony between precision and recall. It summarizes the model's performance.

The four sorts of predictions that a logistic model can make—true positives, false positives, true negatives, and false negatives—must be understood in order to evaluate a confusion matrix.

It is impossible to exaggerate the value of a confusion matrix in assessing logistic models. It's a straightforward, user-friendly tool that gives a precise picture of the model's performance. You can easily spot regions where the model needs to be improved by utilizing a confusion matrix and then changing the model as necessary. The confusion matrix's readability and interpretability make it a handy tool for explaining the model's performance to others.

ROC Curve

A logistic model's effectiveness is graphically depicted by a ROC (Receiver Operating Characteristic) curve. The genuine positive rate (sensitivity) and the false positive rate (specificity) at various threshold values are plotted here. The ROC curve is an effective tool for comprehending the trade-off between the model's sensitivity—it's capacity to detect positive examples-and its avoidance-its capacity to detect negative instances as positive (specificity).

You need to comprehend the two crucial ideas of sensitivity and specificity in order to read a ROC curve. The percentage of real positive events that the model properly recognizes is called sensitivity. The percentage of real negative events that the model properly detects is known as specificity.

The value of a ROC curve in assessing logistic models is in its capacity to show the performance of the model graphically. It enables you to compare sensitivity and specificity trade-offs at various threshold levels. The threshold value that strikes a balance between the model's capacity to accurately detect positive instances and its ability to avoid mistaking negative examples for positive ones can be readily determined by looking at the ROC curve.


It is very critical to evaluate the quality of the logistic model, as it ensures the reliability of model's predictions. Various methods can be used to evaluate its quality. It will help various researchers and businessmen to make precise decisions based model's predictions. Metrics such as accuracy, precision, and recall are used for evaluating Logisitc models.

Updated on: 25-Apr-2023


Kickstart Your Career

Get certified by completing the course

Get Started