What is Labeled Data?

Yana Khare 10 Jun, 2024
4 min read


Many contemporary technologies, especially machine learning, rely heavily on labeled data. In supervised learning, models train using previous input-output pairs to generate predictions or classifications, relying on datasets where each element has an annotation with a label providing background information or indicating expected results. The availability and caliber of labeled data strongly influence the effectiveness and accuracy of machine learning models. This article thoroughly explores labeled data, its creation, application, benefits, and limitations.


  • Learn about labeled data and how it is created.
  • Gain an understanding of the advantages and disadvantages.
  • Discover open-source data labeling tools.
What is Labeled Data?

What is Labeled Data?

Datasets with one or more descriptive labels attached to each data point are labeled data. Training supervised machine learning models requires more information about the data that these labels supply. Labeled data links input data with the appropriate output, such as categories or values, in contrast to unlabeled data, devoid of this contextual information.

How is Labeled Data Created?

Creating this data involves annotating datasets with meaningful tags, which can be manual, semi-automated, or fully automated.

Manual Labeling

Manual labeling is the process of human annotators renewing data points and identifying them appropriately. This procedure can be costly and time-consuming. Furthermore, complex or subjective labeling tasks, such as sentiment analysis or object recognition, often require it.

Semi-Automated Labeling

Semi-automated labeling integrates automated technologies with human supervision. NLP systems, for instance, may automatically tag text data, which people would then check for correctness. Moreover, it is frequently used to label massive datasets, and this method compromises accuracy and efficiency.

Automated Labeling

Automated labeling uses algorithms as the sole tools to assign labels to data points. People frequently utilize this approach for simpler tasks or when they need to quickly process vast amounts of data. Even while automated labeling is not as precise as human or semi-automated approaches, advances in AI are making it more dependable.

Applications of Labeled Data

Let us now look at its application in various domains:

  • Image and Video Analysis: Labeled data is crucial for training models to analyze and interpret images and videos, enabling object detection, facial recognition, and scene understanding.
  • Natural Language Processing (NLP): Labeled data is critical in training models for various NLP tasks, such as sentiment analysis, named entity recognition, and language translation.
  • Healthcare and Medical Imaging: Labeled data is essential for developing predictive models and diagnostic tools in healthcare, improving patient outcomes and operational efficiency.
  • Financial Services: Algorithmic trading, fraud detection, and customer support are just a few financial applications that benefit from labeled data.
  • Recommendation Systems: Develop recommendation systems that tailor user experiences by recommending pertinent articles or goods depending on labeled data.

Advantages and Disadvantages of Labeled Data


  • Enables Supervised Learning: Labeled data is a prerequisite for training supervised learning models. These input-output pairs instruct the model to generate predictions or classifications.
  • Improves Model Accuracy: High-quality data aids in developing more accurate models by offering distinct illustrations of the anticipated results.
  • Facilitates Feature Engineering: Labeled data makes finding and creating pertinent features from unprocessed data more accessible, improving model performance.
  • Supports Validation and Testing: Labels are essential for validating and testing models to ensure they function correctly on unseen data.


  • High Cost and Time-Consuming: Labeling datasets is a costly and time-consuming process that frequently requires extensive manual labor.
  • Potential for Human Error: Manual labeling has a human error risk of producing incorrectly classified data, impairing model performance.
  • Scalability Issues: Scaling labeled data to meet the expanding needs of big data can be difficult, especially for complicated operations requiring specialized expertise.
  • Quality Control Challenges: Maintaining label quality over big datasets might be challenging, which affects the training data’s dependability.
  • Bias Introduction: This may introduce bias if the dataset does not accurately reflect real-world situations or the labeling process is based on subjective assessments.

Open-Source Data Labeling Tools

  • Label Studio: A versatile tool for data labeling, Label Studio allows annotations in text, audio, images, and video. Its customizable interface and compatibility with active learning pipelines make it suitable for various annotation activities.
  • CVAT (Computer Vision Annotation Tool): CVAT, developed by Intel, focuses on computer vision tasks like object recognition and video annotation. In addition, it effortlessly interacts with machine learning frameworks and offers sophisticated functionality for annotating photos and videos.
  • LabelImg: You can make bounding box annotations with LabelImg, a straightforward image annotation tool. This cross-platform tool is perfect for short-term, small-scale item identification tasks since it provides annotations in the PASCAL VOC format.
  • Doccano: Doccano’s design focuses on data annotation and related tasks like sequence labeling and categorization. It provides pre-annotation capabilities and collaboration features that are helpful for NLP applications.
  • DataTurks: DataTurks’ user-friendly platform makes text and picture annotation easy. Also, it offers collaborative tools and API connectivity for efficient processes and supports several annotation types, such as entity recognition and categorization.


Developing efficient machine learning models propels breakthroughs in various fields, from autonomous systems to healthcare, which requires labeled data. As machine learning advances, developing precise, dependable, and scalable AI solutions will be critical.

Frequently Asked Questions

Q1. What is labeled and unlabeled data?

A. Labeled data is information with identified categories or outcomes, aiding machine learning models in understanding patterns. Unlabeled data lacks such classifications.

Q2. What are data labels?

A. Data labels are annotations or tags assigned to data points, providing context or classification for machine learning algorithms.

Q3. Why is labeled data essential in machine learning?

A. Labeled data is crucial in machine learning as it facilitates supervised learning, enabling algorithms to learn relationships between input features and output labels.

Q4. Can machines label data?

A. Yes, machines can label data through techniques like active learning or using pre-trained models for tasks like image recognition or natural language processing.

Yana Khare 10 Jun, 2024

Frequently Asked Questions

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