Search fields are used to match the user's query to one or more results. By default, titles and descriptions are matched.
Boosting individual search field enables you to rank documents higher, based on the field the query matches on. For example: you’re boosting the data field Description higher than the data field Title. When a query contains (part of) the description, matching products will score higher than documents that contain (part of) the query in the title field. You can use the Boost slider, or type directly in the Level field under Actions.
To add a search field for boosting, choose a data field by clicking the drop-down menu. Here you find a list of your basic data fields and custom data fields. Select one and click Add search field. It will now appear in the overview. Adjust the level of boosting and click on Save. Deleting search fields is also possible, through the trashcan icon on the right of each search field.
If the wished field is not available to add, you might need to enable it first. Read how to do this in the article: Use Custom fields. Please note that search fields require the data type to be set to text. You can check or change this via the settings button when editing data fields.
Clickrank
With clickrank, the order of results can be smartly ranked, based on total usage of your Search plugin. With the slider, you determine how much the same questions from others count in the overall score of query/click. Meaning, the results can be less relevant, but lead to higher conversion.