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Government Record Linkage 2D: Exploring the Fellegi-Sunter Algorithm

A powerful method for identifying records that refer to the same entity across different databases.

mysimulator teamUpdated June 2026≈ 3 min read▶ Open the simulation

What is Government Record Linkage?

Government record linkage involves identifying and linking records that refer to the same entity across different databases. This process is crucial for data integration, ensuring comprehensive and accurate information systems in public administration.

The Fellegi-Sunter algorithm provides a probabilistic framework for this task, estimating the likelihood that two records belong to the same individual based on their similarity.

How Does the Fellegi-Sunter Algorithm Work?

The Fellegi-Sunter model is based on Bayesian probability theory. It assigns a score to each pair of records, reflecting how likely they are to refer to the same entity. This score is calculated using the observed similarity between fields in the records and their known error rates.

The algorithm considers both exact matches and partial matches, weighting them according to predefined probabilities of errors in data entry.

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Why Use a 2D Diagram?

A 2D diagram provides an intuitive way to visualize the linkage process. Each axis represents one database, with records plotted based on their similarity scores. This visualization helps users understand how different match thresholds affect the linking results.

By dragging and zooming, users can explore various regions of the diagram, gaining insights into which pairs of records are most likely to be linked.

Real-World Applications

The Fellegi-Sunter algorithm has numerous applications in government and beyond. For instance, it can help in merging voter registration lists with tax records to ensure accurate representation and taxation.

In healthcare, linking patient records from different hospitals can improve the quality of care by providing a complete medical history for each individual.

Frequently asked questions

How does the Fellegi-Sunter algorithm handle errors in data entry?

The algorithm incorporates error rates into its calculations, estimating the probability that two records are a match even if there are discrepancies due to data entry mistakes.

What is the significance of the match threshold in the Fellegi-Sunter model?

The match threshold determines how similar records must be before they are considered a potential match. Adjusting this threshold allows users to balance between false positives and false negatives.

Can the Fellegi-Sunter algorithm be used for non-governmental data linkage?

Yes, it can be applied to any scenario where records need to be linked across different databases, such as in marketing or academic research.

How does the 2D diagram help in understanding the match process?

The 2D diagram visually represents how records from two databases are compared and scored. It helps users see which pairs of records have high similarity scores, indicating a strong likelihood of being linked.

Try it live

Everything above runs in your browser — open Government Record Linkage 2D — Fellegi-Sunter Score Explorer and change the parameters while it is running. Nothing is installed, nothing is uploaded, the whole model lives in one tab.

▶ Open Government Record Linkage 2D — Fellegi-Sunter Score Explorer simulation

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