This document contains information about using bias to tune search results with the Apache Solr Search module.

The Apache Solr Search module’s bias settings enable you to assign search bias to certain aspects of indexed items. Configure bias for a search environment on the Apache Solr search > Settings tab, under Configuration.

Search bias influences the importance of those aspects in search results. Any value except “Omit” or “Ignore” increases that aspect’s score in the results. The higher the score, the more those aspects will influence the search results. You can assign values from 0.1 to 21.0 when you set a bias. You can assign bias by:

• Bias by node attributes
• Bias by content type
• Bias by node fields

Bias by node attributes

Using the Result biasing section, you can add search bias to favor nodes that are or have:

• Sticky at top of lists
• Promoted to home page
• More recently created
• More comments
• More recent comments

Bias by content type

Using the Type biasing and exclusion section, you can add search bias to favor nodes of particular content types. For example, you might want to favor announcements over blog posts.

Bias by node fields

Using the Field biases section, you can add search bias based on the field in a node in which the search term appears. For example, you might want to give extra weight when the search term appears in a node’s title or H1 headers and less weight when the search term appears in rendered comments.

Setting a field’s value to Omit means that the field will not be searched.

Using bias to tune search results

Bias by node attributes

Using the Result biasing section, you can add search bias to favor nodes that are or have:

• Sticky at top of lists
• Promoted to home page
• More recently created
• More comments
• More recent comments

Bias by content type

Using the Type biasing and exclusion section, you can add search bias to favor nodes of particular content types. For example, you might want to favor announcements over blog posts.

Bias by node fields

Using the Field biases section, you can add search bias based on the field in a node in which the search term appears. For example, you might want to give extra weight when the search term appears in a node’s title or H1 headers and less weight when the search term appears in rendered comments.

Setting a field’s value to Omit means that the field will not be searched.