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Enhancing NLP Precision – The Power of Custom NER Models

Blog | August 21, 2023 | By Amit Phatak

Imagine reading a news article about a major event. You’re in a hurry and you just want to get the gist of it as quickly as possible. You want to know who, what, where, and when of the story. What do you do? You look for the names of people, places, organizations, dates, and other such elements in the article. These are called named entities, the building blocks of “meaning” in the natural language. Named Entity Recognition (NER) is the process of finding and classifying these entities in unstructured text. It is a critical component of modern Natural Language Processing (NLP), as it allows machines to understand and process human language more effectively.

The rapid adoption of ChatGPT has led enterprises to scramble to provide a natural language-capable interface to their users. This then makes it essential that the natural language provided as input to systems is interpreted correctly in the context of the task being performed. While generic NER models provide a broad baseline, custom NER models that are tailored to specific domains significantly enhance the accuracy and relevance of specific NLP tasks.

This primer is an attempt at exploring the world of NER, underlining its significance, applications, and the urgent need for custom NER models that cater to specific domains.

Unveiling Named Entity Recognition (NER) and Its Role in NLP

Significance of NER in Understanding and Processing Language 

NER seeks to locate and identify specific words (named entities) in the input text into a set of predefined categories such as person names, organizations, locations, dates, quantities, monetary values, and the like. NER helps convert unstructured text into structured data by tagging individual entities to their appropriate category. For example, in the sentence “Sam Altman is the CEO of OpenAI”, NER would identify “Sam Altman” as a person and “OpenAI” as an organization.

The Role of Custom NER Models in Modern NLP

NER’s Impact on Search, Question-Answering, and Virtual Assistants 

NER plays an important role in a variety of NLP tasks. Here are a few ways in which it enhances NLP tasks:

  • Search: Search engines benefit from NER as it helps them enhance search results. For instance, if a user is looking for “Apple’s latest products”, understanding that “Apple” refers to the tech company (and not the fruit) can significantly improve search relevance.
  • Question-Answering: NER assists question-answering systems in understanding the entities in a question to provide more accurate answers. For example, when querying “Who is the CEO of Tesla?”, the system recognizes “Tesla” as a company and retrieves relevant information about its CEO.
  • Virtual Assistants and Chatbots: These systems utilize NER to understand user queries more effectively and provide appropriate responses. For example, recognizing named entities in user input helps in contextualizing the conversation and provide relevant responses.

The above examples are enough to see just how foundational NER is to modern NLP applications. By providing the essential step of recognizing and categorizing real-world objects (entities) mentioned in the text, it enriches the understanding and processing capabilities of various systems.

Custom NER for Domain-Specific Complexities

There are multiple general-purpose NER models that can identify and categorize entities. In most cases, they are not sufficient for domain-specific applications. Industries such as finance, manufacturing, healthcare, legal et al. often have specialized terminologies, jargon, and nuances that generic models struggle with. This can happen either because the entities are not commonplace in the training data that was used for training the model or the categories themselves are different from the ones the model was trained on. Thus, to extract accurate and meaningful entities from texts for domain-specific use, there is a pressing need for custom NER models tailored to those specific domains.

Training Custom NER Models

Training a custom NER model typically involves the following steps:

  • Data Collection and Annotation: As with any AI/ML model, a sufficiently large representative dataset relevant to the domain is collected. This dataset should comprise text samples containing the entities of interest. Human annotators then label the entities in the text, marking out their start and end positions and assigning appropriate categories to them.
  • Model Selection: Depending on the size of dataset and the task complexity, an appropriate machine learning or deep learning model is chosen. Earlier, traditional models like Conditional Random Fields (CRFs) were popular. Lately though, deep learning architectures like Bi-directional LSTM (BiLSTM) with attention mechanisms or transformers have gained prominence for NER tasks due to their superior performance.
  • Training: With the representative annotated dataset, the chosen model is trained to recognize and classify entities. This involves feeding the model with chunks of text and training it to predict the annotated entities.
  • Validation and Testing: The trained model is then validated on a separate validation set of annotated data to gauge its accuracy, precision, recall, and F1 score. Tweaks and refinements are made based on the model’s performance on this dataset. Finally, the model is tested on entirely unseen data to ensure its robustness and generalization capabilities.
  • Iteration: As with all machine learning models, custom NER models benefit from iterative refinement. The model is retrained and enhanced as more data becomes available or the domain evolves.

Advantages of Custom NER Models

Custom NER models offer multiple benefits over generic NER models. For instance:

  • Higher Accuracy: Since these models are tailored to a specific domain, they are naturally more attuned to its nuances and terminologies, resulting in better recognition and classification of entities.
  • Flexibility and Evolution: Custom NER models can be iteratively improved upon or retrained to accommodate new terminologies or entity types as the domain evolves.
  • Data Privacy: Organizations can ensure data security by building and hosting their custom NER models, negating the need to share sensitive data with third-party vendors.

Unlocking the Potential of Custom NER Models

Advantages and Future Implications of Custom NER Models

In the fast and furious world of Natural Language Processing, NER stands for order and discipline. A beacon of structure, converting the chaos of unstructured text into organized, categorized data. While general NER models serve as a useful starting point, the nuanced requirements of specific industries and domains necessitate custom models. The process of training these bespoke models – complex and intricate as it may be – yields results that are far more accurate. In a world increasingly reliant on data, the capability to accurately recognize and classify every nugget of information contained in texts is invaluable, and this is precisely the promise of custom NER models.

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About the Author
Amit Phatak is a proven leader adept at driving innovation through emerging technologies. With expertise in product development, monetization, and a passion for technology and business, Amit excels in hands-on development and customer engagement. A proponent of agile practices, automation, and emerging tech, he specializes in data, analytics, and AI/ML solutions.
Amit PhatakVP & Head of Decision Intelligence | USEReady
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