What is Recall?

  • Editor
  • January 9, 2024

What is recall? In the context of artificial intelligence (AI) and machine learning, it is a critical metric used to evaluate the performance of a model. It measures the model’s ability to correctly identify all relevant instances within a dataset.

Specifically, recall is the ratio of true positives (correctly identified instances) to the sum of true positives and false negatives (instances incorrectly marked as irrelevant). This metric is particularly important in scenarios where missing a relevant instance has significant consequences, such as in medical diagnosis or fraud detection.

Looking to learn more about recall and its use in AI? Keep reading this article written by the AI enthusiasts at All About AI.

What is Recall? : The Treasure Hunt in Artificial Intelligence

Recall is like playing a game of finding hidden treasures. Imagine you have a robot friend who is learning to find hidden treasures. In this game, ‘recall’ is a way to check how good your robot friend is at finding all the hidden treasures in a big field. If there are 100 hidden treasures and your robot finds 90 of them, then its recall is really good because it found most of the treasures. But if it only finds 10, then its recall isn’t very good. So, recall helps us understand how well the robot can find all the things it’s supposed to find.

Why Precision and Recall Matter More Than Accuracy in Certain Scenarios:


While accuracy is often seen as the go-to metric for evaluating artificial intelligence models, it doesn’t always provide a complete picture. This is where precision and recall come into play.

Here are some scenarios where precision and recall matter more than accuracy.

Scenario 1: Medical Diagnostics

In medical diagnostics, especially in detecting diseases like cancer, missing a positive case (low recall) can be life-threatening. Accuracy alone is misleading if the model only correctly identifies healthy patients but fails to detect sick ones.

Scenario 2: Fraud Detection

In the context of fraud detection in finance, a high recall is crucial. A model with high accuracy but low recall might overlook significant fraudulent transactions, leading to substantial financial losses.

Scenario 3: Spam Filtering

For spam filters in email systems, a balance between precision and recall is essential. High recall ensures all spam is caught, but if precision is low, important emails might be incorrectly classified as spam.

Scenario 4: Object Detection in Autonomous Vehicles

In autonomous vehicles, object detection systems must have high recall to identify all potential hazards. However, accuracy alone is insufficient as missing a single hazard (like a pedestrian) could be catastrophic.

Why Must We Balance Recall with Precision?


Balancing recall with precision is essential because focusing on one at the expense of the other can lead to suboptimal outcomes.

The balance depends on the specific application; for instance, in cancer screening, high recall might be prioritized over precision to ensure all potential cases are identified.

Ensuring Comprehensive Detection:

Balancing recall and precision ensures that a model not only identifies as many relevant instances as possible (high recall) but also maintains the relevance of these identifications (high precision).

Reducing False Positives:

High precision is necessary to reduce false positives. In medical testing, for instance, too many false positives can lead to unnecessary anxiety and medical procedures.

Maximizing Resource Efficiency:

In areas like law enforcement or quality control, high precision minimizes resource wastage on false leads or non-defective products, while high recall ensures no critical cases are missed.

Maintaining User Trust:

For consumer-facing applications like recommendation systems, balancing precision and recall is key to maintaining user trust and satisfaction.

Adaptability Across Different Domains

Different applications require different precision-recall balances. For instance, in legal document search, precision might be more important than recall to avoid irrelevant information.

How Can We Improve Recall in Our Models?

Improving recall in AI models can be approached by:

  • Enhancing Data Quality: By improving the quality and diversity of training data, models can learn to identify a wider range of relevant instances.
  • Adjusting Classification Thresholds: Lowering the threshold for classifying an instance as positive can increase recall, though it might affect precision.
  • Implementing Data Augmentation: Augmenting data through techniques like synthetic data generation can provide more examples for the model to learn from, improving recall.
  • Utilizing Advanced Algorithms: Employing algorithms specifically designed for high recall, like anomaly detection or certain deep learning architectures, can significantly improve performance.

When is Recall the Right Metric to Use?

Recall becomes a critical metric in situations where the consequences of missing a positive instance are far more significant than incorrectly identifying a negative instance as positive.

This is often the case in fields like healthcare, public safety, and critical system monitoring, where failing to detect a rare but important event could have grave consequences.

In such scenarios, a model that prioritizes recall ensures that it captures as many relevant instances as possible, which is paramount.

Calculating Precision and Recall: A Practical Example


Let’s consider a practical example in the context of disease screening. Suppose a model is used to screen 1,000 patients for a specific disease. Out of these, 100 patients actually have the disease.

  • True Positives (TP): The model correctly identifies 90 of these patients.
  • False Negatives (FN): The model misses 10 patients who have the disease.
  • False Positives (FP): The model incorrectly identifies 30 patients as having the disease, who do not.

In this scenario:

This example illustrates how precision and recall provide a more nuanced understanding of a model’s performance, especially in critical applications like disease screening.

Want to Read More? Explore These AI Glossaries!

Immerse yourself in the domain of artificial intelligence using our thoughtfully organized glossaries. Whether you’re a novice or a proficient learner, there’s always something fresh to explore!

  • What Is Contrastive Language Image Pretraining?: It involves training models to understand and generate content by simultaneously learning from language and images.
  • What Is Controlled Vocabulary?: It refers to a predetermined set of terms and phrases used to index and retrieve content in a systematic way.
  • What Is Control Theory?: It refers to the systematic design of controllers that manage how AI systems behave in response to external inputs or environmental changes.
  • What is Conversational AI?: Conversational AI refers to the application of artificial intelligence in creating systems capable of understanding, processing, and responding to human language in a natural and intuitive way.
  • What Is a Convolutional Neural Network?: It is a deep learning algorithm particularly adept at processing data with a grid-like topology, such as images.


In AI, recall is a metric that measures the ability of a model to identify all relevant instances in a dataset.

An example of recall is a spam filter correctly identifying all spam emails in your inbox.

The three main types of recall are free recall, cued recall, and serial recall, used in different contexts within AI and psychology.

Recall is crucial as it ensures that a model identifies all potential instances of interest, which is particularly vital in scenarios where missing an instance could have significant negative consequences.


Understanding recall in AI is fundamental for developing effective and reliable models, especially in critical applications. Balancing recall with precision, depending on the specific requirements of the task at hand, is key to achieving desired outcomes.

This article was written to answer the question, “what is recall,” discuss its extensive use in the world of AI. If you’re looking to enhance your AI knowledge beyond concepts like recall, check out the other topics we’ve covered in our AI Definitions Guide.

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Dave Andre


Digital marketing enthusiast by day, nature wanderer by dusk. Dave Andre blends two decades of AI and SaaS expertise into impactful strategies for SMEs. His weekends? Lost in books on tech trends and rejuvenating on scenic trails.

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