Entity Resolution (ER) is a critical data management process used to identify, link, and merge records that correspond to the same real-world entities across different databases or within a single database.In the context of a B2C retail company, Entity Resolution helps consolidate customer information from multiple sources, ensuring data accuracy and consistency. This process is paramount for improving data quality and trust, enabling businesses to achieve a unified or customer 360, view of their customers. By accurately identifying unique customers, companies can enhance personalized marketing strategies, improve customer service, and make informed business decisions. Entity Resolution lays the foundation for robust data governance, ensuring that data across the organization is accurate, consistent, and actionable.
For this tutorial, we will look at Entity Resolution at a fictional B2C retail company specializing in luggage and travel gear, akin to Away.com; we face the challenge of entity resolution in our customer database. We aim to identify our best customers and eliminate duplicate records, streamlining our marketing efforts and enhancing customer service. To tackle this, we will leverage the RecordLinkage Python package, a powerful library for linking and deduplicating records.
First, let's explore the data model in our unioned customer table. Our data includes columns such as first_name
, last_name
, city
, country
, internal_id
, MAID
, braze_id
, and shopify_id
. These fields will be instrumental in our entity resolution process.
Example Records:
import pandas as pd
# Load the dataset
df = pd.read_csv('/mnt/data/customers_updated.csv')
# Display the first few records
df[['first_name', 'last_name', 'city', 'country', 'internal_id', 'MAID', 'braze_id', 'shopify_id']].head()
For our problem, we'll employ blocking and comparison techniques to identify potential duplicates efficiently. Blocking is a technique used in record linkage to efficiently identify duplicate records within or across datasets. The primary goal of blocking is to reduce the computational complexity of the matching process by limiting the number of comparisons that need to be made. Let's delve deeper into how blocking works and why it's important in record linkage.
Blocking makes it possible to scale record linkage processes to larger datasets, which would be impractical to handle using exhaustive comparison methods. Blocking enhances record linkage by minimizing comparisons, thus accelerating the process for large datasets. It boosts efficiency, and when executed properly, it can also maintain or enhance accuracy by concentrating comparisons where necessary. This method enables the scalability of record linkage to handle larger datasets, which would be cumbersome with exhaustive comparison techniques.
import recordlinkage
# Create an indexer and specify the blocking variable
indexer = recordlinkage.Index()
indexer.block('country')
# Index the DataFrame
candidate_links = indexer.index(df)
After identifying candidate pairs through blocking, we proceed to compare these pairs on multiple attributes. The RecordLinkage package offers a variety of comparison methods, including exact matches, string similarity, numerical comparisons, and more. Among these, the choice of method depends on the nature of the data being compared.
Choosing the Comparison Method:
For our customer data, focusing on first_name
, last_name
, city
, and country
, we apply both exact matching and string similarity comparisons. The rationale behind selecting a particular method lies like the data:
city
and country
fields where matches are expected to share identical values, making it straightforward and highly reliable for identifying duplicates.first_name
and last_name
fields, where minor variations in spelling can occur due to typos or alternate spellings. Here, we employ the Jaro-Winkler similarity method.Why Jaro-Winkler?
The Jaro-Winkler method is particularly suited for short strings such as names, where it excels in accounting for common typographical errors and variations. It improves upon the basic Jaro similarity by giving more weight to a shared prefix, assuming that discrepancies are more likely to occur at the end of strings. This characteristic makes it highly effective for name comparisons where prefixes are often correct, even in minor errors or variations.
The decision to set a threshold of 0.85 for the Jaro-Winkler comparisons was made to strike a balance between recall and precision. A threshold of 0.85 ensures that only records with a high degree of similarity are considered matches, reducing the likelihood of false positives while still capturing a significant portion of true matches.
Alternative Comparison Methods:
RecordLinkage offers several other comparison methods, each suited for different types of data and comparison needs:
Each of these methods has its applications, depending on the nature of the data and the specific requirements of the entity resolution task. The choice of the Jaro-Winkler method in our context was guided by its effectiveness in handling the variations and errors typically found in first and last names within customer records.
Back to the code, we can append the following to our script.
# Initialize the comparison object
compare = recordlinkage.Compare()
# Add comparison tasks
compare.exact('city', 'city', label='city')
compare.string('first_name', 'first_name', method='jarowinkler', threshold=0.85, label='first_name')
compare.string('last_name', 'last_name', method='jarowinkler', threshold=0.85, label='last_name')
# Execute the comparison
features = compare.compute(candidate_links, df)
In this step, we've meticulously tailored our comparison methods to align with the characteristics of our data, utilizing exact matching for geolocation attributes and the Jaro-Winkler similarity for personal names. This dual approach, underpinned by strategic thresholding, ensures a robust and sensitive mechanism for identifying potential duplicates, laying the groundwork for effective entity resolution.
The output of the RecordLinkage process is a DataFrame containing pairs of indices from our original dataset that are likely to represent the same entity based on the criteria we set. Each pair is accompanied by a similarity score for each comparison field, reflecting the degree of match according to the Jaro-Winkler method.
let's examine an output derived from our customer dataset.
internal_id | first_name | last_name | city | country | MAID | braze_id | shopify_id |
---|---|---|---|---|---|---|---|
1 | John | Doe | New York | USA | 12345 | abcde | zyxwv |
2 | Jon | Doe | New York | USA | 12345 | fghij | zyxwv |
3 | Jane | Smith | Los Angeles | USA | 67890 | klmno | stuvwx |
# Classification
matches = features[features.sum(axis=1) > 2] # Assuming a simple threshold
print(matches.head())
After running our RecordLinkage process, we find that records 1 and 2 are identified as a match with the following scores:
These scores indicate a high likelihood that records 1 and 2 represent the same individual, John Doe, despite the slight variation in the spelling of the first name ("John" vs. "Jon"). The high similarity scores across all compared fields, especially the perfect matches in last_name
, city
, and country
, reinforce this conclusion.
Identifying such matches allows us to take several important actions to enhance the quality of our customer data:
MAID
, braze_id
, shopify_id
) and any other relevant information from the matching records.Through this implementation, we've streamlined our customer database, enhancing our ability to engage effectively with our clientele. The RecordLinkage package has proven to be an invaluable tool for our entity resolution needs, offering a flexible and efficient approach to identifying and merging duplicate records.
For further exploration, readers are encouraged to delve into the advanced features of the RecordLinkage package, such as machine learning classifiers for match decision-making. Additionally, continuously updating and refining the entity resolution process is crucial as new data becomes available, ensuring ongoing data quality and reliability.
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