What is Entity resolution

Introduction to Entity Resolution

In the world of big data, businesses have to face the challenge of integrating multiple sources of data that may have different formats or structures. In many cases, this results in duplicated records with slightly different attributes. This makes it difficult for organizations to draw accurate insights from their data, which can ultimately impact their bottom line.

Entity resolution, also known as record linkage, is the process of detecting and removing duplicate records from a dataset. This involves identifying records that describe the same real-world entity and merging them together, thereby creating a single representation of that entity.

Entity resolution is a critical step in data integration and data quality management. It has many applications across different industries, including web search, social media analysis, and customer data management.

In this article, we'll explore the basics of entity resolution, the challenges involved, and some common techniques and algorithms used to tackle these challenges.

Challenges in Entity Resolution
  • Missing Data
  • When integrating data from different sources, some records may contain missing data or non-standardized values. For example, one source may have a missing middle name, while another source may have a full name. This can make it difficult to match records based on attributes alone.

  • Similar but Different Attributes
  • Records may have attributes that describe the same entity, but these attributes may have slight variations. For example, two records may have different spellings of the same name or different phone number formats.

  • Large Datasets
  • In large datasets, the number of comparisons required to resolve all possible pairs of records can quickly become unmanageable, even with advanced computational resources.

  • Dynamic Data
  • Data is constantly changing, and new records may be added or updated. As a result, entity resolution is an ongoing process that requires regular updates to maintain accuracy over time.

Techniques and Algorithms for Entity Resolution

Entity resolution can be performed in various ways, depending on the dataset and types of records being compared. Here are a few common techniques and algorithms:

  • Exact Matching
  • This technique involves comparing records based on exact attribute matches. For example, if two records have the same name and phone number, they are considered a match. This is often used for small datasets with low levels of variation in attributes.

  • Fuzzy Matching
  • This technique involves comparing records based on attributes that are similar but not identical. This is useful in cases where there may be variations in spelling, formatting, or syntax. Fuzzy matching algorithms assign a score to each pair of records based on their similarity, and a threshold is set to determine whether a pair is a match or not.

  • Blocking
  • This technique involves dividing the dataset into smaller blocks based on a specific attribute, such as zip code or surname. Within each block, records are compared to determine potential matches. This can greatly reduce the number of comparisons required, making it more efficient for large datasets.

  • Probabilistic Matching
  • This technique uses statistical models to calculate the probability that two records refer to the same entity. It takes into account the probability of errors or variations in each attribute value and produces a score that represents the likelihood of a match. This technique is useful for datasets with noisy data and a high degree of variation between attributes.


Entity resolution is a critical step in data integration and data quality management. It requires a deep understanding of the dataset and the types of records being compared. By using one or more of the techniques and algorithms described above, organizations can improve the accuracy and reliability of their data insights, leading to better decision-making and competitive advantage.