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Importing Contact Data Into Tern
How Tern looks up contacts during an import
How Tern looks up contacts during an import

Understand how Tern

David Shull avatar
Written by David Shull
Updated over a week ago

Welcome to the Tern Help Center! This article aims to provide you with a comprehensive understanding of how Tern manages duplicate lookups within your contact database. This process is crucial for maintaining the accuracy and integrity of your contact information, especially when dealing with multiple entries that may seem similar.

Understanding Duplicate Lookups

Duplicate lookups occur when there are multiple entries in the database that could potentially represent the same contact. This can happen due to shared email addresses, slight variations in names, or when importing data from different sources.

The Role of Import IDs and Email Addresses

Tern utilizes a two-pronged approach to handle duplicates:

  1. Import IDs: Tern prefers to use Import IDs as the primary method for identifying unique contacts. An Import ID is a unique string of characters assigned to each contact. If a contact row during import contains an Import ID, Tern uses this ID to check against existing contacts. If a match is found, Tern updates the existing contact with the new information. If there's no match, a new contact is created.

  2. Email Addresses: In the absence of an Import ID, Tern falls back on email addresses as identifiers. However, this method can be less reliable due to the potential for shared emails or slight name variations.

The Duplicate Lookup Process

  1. Check for Import ID: Tern first checks if an import ID is present in the imported data. If it is, the system looks for a matching import ID in the database.

    • Existing ID: If a match is found, Tern updates that contact.

    • No ID Found: Tern creates a new contact.

  2. Fallback to Email Address: If no Import ID is present, Tern uses the email address for identification.

    • No Email: If there’s no email, Tern creates a new contact by default, assuming it's a unique entry.

    • Email Present: Tern checks if the email address matches an existing contact.

      • Unique Email: If the email is unique, Tern either updates the existing contact or creates a new one.

      • Shared Email: If the email is shared, Tern looks for additional matching criteria like the contact's name. If a name match is found, Tern updates the contact. Otherwise, it may create a new entry, potentially leading to duplicates.

Best Practices for Avoiding Duplicates

  1. Use Import IDs: Always include Import IDs for each contact when importing data. This ensures each contact is treated as unique.

  2. Clean and Consistent Data: Ensure your data is clean and consistent before import. Standardize names and email addresses to reduce the chances of duplicates.

  3. Review Shared Emails: Pay special attention to contacts sharing an email address. Assign distinct Import IDs to each to avoid confusion.

  4. Regular Database Audits: Periodically review your database to identify and merge any duplicates that may have slipped through.


Understanding and effectively managing duplicate lookups is crucial for maintaining an efficient and accurate contact database in Tern. By following these guidelines and using the Import ID system judiciously, you can significantly reduce the occurrence of duplicate contacts and maintain the integrity of your database. For any further assistance, feel free to reach out to Tern's support team.

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