The Significance of Data Labeling and the Role of Snorkel in Enhancing Machine Learning

In the realm of machine learning (ML) and artificial intelligence (AI), data is the bedrock upon which models are built and refined. However, raw data, while abundant, often lacks the structure and organization necessary for effective learning. This is where data labeling comes into play. Data labeling is the process of annotating or tagging data points with relevant metadata or labels, providing context and meaning to otherwise unstructured information. This process is crucial for numerous reasons, and its importance cannot be overstated in the development and deployment of ML models.

  • First and foremost, labeled data serves as the training material for ML algorithms. Supervised learning, one of the most prevalent paradigms in ML, relies heavily on labeled datasets to learn the relationship between input features and target outputs. Without accurately labeled data, ML models would struggle to generalize patterns and make accurate predictions. Thus, the quality and accuracy of labels directly influence the performance and reliability of ML systems.
  • Furthermore, data labeling facilitates the creation of ground truth datasets, which serve as benchmarks for evaluating model performance. By comparing model predictions against accurately labeled data, ML engineers can assess the efficacy of their algorithms and identify areas for improvement. This iterative feedback loop is essential for refining ML models and enhancing their robustness in real-world scenarios.
  • Additionally, labeled data enables domain-specific insights and knowledge extraction. By categorizing data points into meaningful classes or attributes, organizations can derive valuable insights about customer preferences, market trends, and business operations. These insights can inform strategic decision-making and drive innovation across various industries, from healthcare to finance to e-commerce.

Despite its undeniable importance, data labeling can be a labor-intensive and time-consuming process, especially when dealing with large volumes of unstructured data. Manual labeling by human annotators is often prone to errors, inconsistencies, and biases, leading to suboptimal model performance. This is where automated labeling tools like Snorkel come into play.

Snorkel - Programmatically Build and Manage Training Data

  • Snorkel is a powerful framework designed to streamline the data labeling pipeline and mitigate the challenges associated with manual annotation. By leveraging weak supervision techniques, Snorkel enables ML teams to programmatically generate labels from noisy or imperfect sources, such as heuristics, rules, or distant supervision. This approach not only accelerates the labeling process but also improves label quality by aggregating information from multiple sources and learning from noisy signals.`

Moreover, Snorkel provides a unified platform for managing the entire data labeling workflow, from data ingestion to model training. Its flexible and extensible architecture allows users to customize labeling functions, integrate with existing ML pipelines, and adapt to evolving data requirements. By automating tedious labeling tasks and empowering ML engineers to focus on high-level model design and optimization, Snorkel enhances productivity and accelerates the pace of innovation in ML research and development.

Data Labeling Labs

In this series of labs, we will learn fundamental aspects of Snorkel using 3 examples provided by Snorkel team.

We consider a canonical machine learning problem: classifying spam

  • 01_spam_tutorial: This tutorial dives deep into how we can create, analyze, and use labeling functions for the spam classification task.
  • 02_spam_data_augmentation_tutorial: This tutorial demonstrates how to write, combine and apply transformation functions for performing data augmentation.
  • 03_spam_data_slicing_tutorial: This tutorial shows how we can use slicing functions to identify important slices of the data, for monitoring and improved performance.


  1. Github Lab-1
  2. Jupyter Lab installed in your system (important to have it installed)

Setting up the lab

  1. Open the local mlops_labs directory using Visual Studio Code(VSC) and open a new terminal inside VSC.
  2. Create a new working directory for this lab(e.g. data_labeling_labs).
  3. Move into the working directory using the command cd data_labeling_labs in your terminal.
  4. Get the requirements.txt file from here.
  5. Create a virtual environment(e.g. data_labeling_env).
  6. Activate the environment and install the required packages using pip install -r requirements.txt.
  • Note(Windows users): If you get the error error: Microsoft Visual C++ 14.0 or greater is required while running pip install -r requirements.txt, install C++ build tools as show in this video.

Getting the necessary files

Get the required files for this lab from the MLOps repo.

GitHub link

Project Structure:

    └── data_labeling_labs/
        ├── requirements.txt
        ├── data_labeling_env/
        ├── data/
        ├── 01_spam_tutorial.ipynb
        ├── 02_spam_data_augmentation_tutorial.ipynb
        ├── 03_spam_data_slicing_tutorial.ipynb

Running the notebooks

  1. To run the jupyter notebooks, you first have to link your virtual environment to jupyter-lab.
  2. Run the following command in your terminal to do this. Pass the name of your virtual environment to --name argument.
     python -m ipykernel install --user --name=data_labeling_env
  3. Run jupyter lab.
  4. Select your virtual environment as your notebook’s kernel by going to the Kernel menu -> Change kernel -> select your virtual environment.
  5. Continue with the jupyter notebook.

Notebook-1: spam tutorial

  • Tip: To open any of the links in the following notebook, right-click on the links and select “open in new tab” option otherwise those websites will replace the notebook. If it happens, simply click “back” in your browser to return to the notebook.