Skip to main content
  • Subscribe by RSS
  • Ex Libris Knowledge Center

    How Does Primo Blending Work?

    • Article Type: Q&A
    • Product: Primo


    How Does Blending Work?


    The blending settings in the Primo Back Office can be used to influence how results from a specific search engines are ranked in a blended result list.

    This is for example useful to boost local records higher up in the result list when blended with Primo Central records. Blending values can be configured by search engine (Local, Primo Central, EBSCO adaptor, etc.).

    Note that it only has to be configured if to boost or de-boost results from a specific search engine. Otherwise there is no need to touch it.

    Several parameters can be used to influence the ranking of blended records.

    This article:

    • Defines the configurable parameters.

    • Provides recommendations for configuring a local search engine when blended with CDI.

    • Provides attached a document with more details and further recommendations.

    • It's possible to also define and configure other settings to influence the ranking of records coming from the local search engine, for example by changing the boost of certain fields.

    • This article only deals with the blending settings.

    Locate the blending configuration sections in the Primo back office under:

    Primo Home > Advanced Configuration > Search Engine Configurations – Blending

    Configurable parameters:

    1. Minimum hit rank for combining – 

      This value uses each individual record's initial rank in the result list (based on its fit to the user’s search) to decide if it should be included in the blending process.

      Setting this to High means that only if the record has a high ranking will it be blended. Other values are Medium and Low.

      We generally recommend that the Local Search Engine settings be defined at either Medium or Low, since these records usually have a lower ranking by definition (Primo Central should be set to High).

    2. Combine Location – 

      This parameter defines in which position in the result list the first blended record should be placed.

      Records that are boosted via the blending settings can appear from the second position onwards.

      The top position is always reserved for the top record based on the hit rank.

      Values for the Combine Location parameter can be Top (the 2nd record), Center (the 5th record), Bottom (the 9th record).

      These settings should not overlap between the various sources being blended (if the Local is set to Top, Primo Central should not have the identical setting).

    3. Number of results to award – 

      This field specifies the number of records to boost. The system will sufficiently boost the first record to ensure that it displays on the first page of the results. The remaining records receive a boost that is equivalent to the boost of the first record, but they will display according to their rank.

      If this parameter is left blank, the Minimum hit rank for combining and Combine Location fields are not used.

    4. Constant factor – 

    All records from this search engine are multiplied by the constant factor. It cannot be zero. If it is set to 1, there will be no boost.

    The Constant Factor setting is not part of blending; it is applied regardless of whether the “force blending” checkbox is checked.
    This is indicated by the separateness of this setting from the other settings and the fact it isn’t grayed out when force blending is not enabled.

    Recommended settings:

    If there are only two search engines – local and CDI – the following settings are recommended on the local search engine only. No special configuration is needed for CDI:

    • Minimum hit rank for combining: Medium

    • Combine Location: Top

    • Number of Results to reward: 3

    • Constant factor: 4.0

    When an “Everything” tab is defined with local and Primo Central results, only the “force blending” checkbox for the Local Search Engine should be checked so that it will boost the local results above Primo Central.

    Additional Information

    Refer to the attached PDF document for more information on how the parameters are applied and what the recommended settings are for more than two search engines.


    Attached file

    • Article last edited: 12/18/2014