Machine learning relevancy in AI Search

  • Release version: Zurich
  • Updated January 20, 2026
  • 3 minutes to read
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    Summary of Machine Learning Relevancy in AI Search

    AI Search utilizes machine learning to enhance the relevancy of search results based on user interactions, automatically prioritizing the most relevant results for each query. This functionality is enabled by default and cannot be modified by users.

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    Key Features

    • Relevancy Models: Each search profile has its own relevancy model that computes scores for returned results, ensuring the highest-scoring documents appear first. These models are not viewable or modifiable by users.
    • Search Signals: AI Search collects data on user interactions with search features (input fields, suggestions, filters) to refine relevancy models continually.
    • Tuning Process: Every 30 days, AI Search evaluates and updates relevancy models using historical data and A/B testing, ensuring the best model is active.
    • Auto-Complete Suggestions: A separate relevancy model ranks suggestions based on freshness and title matches, but it is not trained through user interactions.
    • Relevancy Score Viewing: Administrators can view relevancy scores for search results using the Search Preview UI in the Advanced AI Search Management Tools application.

    Key Outcomes

    By leveraging machine learning for relevancy tuning, AI Search significantly improves the accuracy of search results over time. However, successful tuning requires at least 10,000 search event signals; otherwise, the original relevancy model will remain active. Additionally, upgrades to the Zurich release may alter default relevancy scores.

    AI Search displays the most relevant search results for a query first. Machine learning automatically tunes search result relevancy scoring for search experiences based on aggregated user interactions.

    Machine learning relevancy is automatically enabled and isn't configurable.

    Relevancy models and scoring

    AI Search uses a relevancy model to compute a relevancy score for each result returned by a search. Documents with higher relevancy scores appear first in the result set. A result's relevancy score is specific to the particular document, search terms, and user associated with the query.

    Each search profile includes its own relevancy model. You can't view, modify, or delete this relevancy model.
    Note:
    AI Search doesn't apply relevancy ranking to *** universal wildcard queries. Results from *** queries appear in an unspecified order.

    Search signals and machine learning relevancy tuning

    AI Search UX components record signals associated with user searches. These search signals include data on how search users interact with the search input field, auto-complete suggestions, facet and source facet bucket filters, Genius Result answer cards, and search results. To learn more about how search signals are recorded and stored, see Search signals.

    Machine learning relevancy uses data from these search signals to intelligently tune relevancy models on a continual basis. Every 30 days, AI Search computes a new version of each relevancy model, iteratively modifying its parameters and regression testing it against aggregated search signal data for the search profile. When this tuning process is complete, AI Search compares the existing and new relevancy models to see which one produces better matches for user search behavior as recorded in the historical signal data.

    If the new relevancy model produces better results with the signal data, AI Search uses its modified parameter values to perform A/B testing evaluations of live search traffic for the search profile. These evaluations test individual parameter changes to verify that they produce better search relevancy.
    Note:
    For details on the search query parameter evaluation framework used to perform A/B testing evaluations, see Search query parameter evaluation framework.

    If the new model outperforms the original model in both the historical search-match comparison and the A/B testing, AI Search sets it as the active relevancy model for the search profile, overwriting the existing relevancy model. The updated relevancy model remains in use until the next tuning cycle begins.

    These relevancy model tuning processes occur separately for each search profile. Changes made to the relevancy model in one search profile don't affect relevancy models in other search profiles.
    Note:
    When you upgrade to Zurich from a previous release, the default relevancy scores for your search results may change. Relevancy models trained in the previous release should continue to produce the same result ordering. Models trained more than one release ago may revert to the default relevancy model.

    Successful relevancy tuning requires at least 10,000 stored search event signals for a search profile. If the search profile has fewer than 10,000 signals stored, relevancy tuning fails with an error message and AI Search continues to use the original relevancy model for that search profile.

    Relevancy model for auto-complete suggestions

    AI Search uses a dedicated relevancy model to rank records for display as auto-complete suggestions in the search field. This relevancy model scores records based on their freshness and on search query term matches in their title fields. The system doesn't train this auto-complete suggestion relevancy model. For details on configuring auto-complete suggestions, see Auto-complete suggestions in AI Search applications.

    Viewing relevancy scores for search results

    Search administrators can view the scores for search results in the Search Preview UI from the Advanced AI Search Management Tools ServiceNow® Store application. For details on using this feature to investigate search behavior, see Search Preview UI for AI Search.