I'm still working on collective.solr branch. To help our customer to understand how certain documents has been scored, I've included in Plone search results an configurable option - debug query.

Using it you can check directly in Plone, Solr score explanation (it's toggled by jQuery).

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For one of our customer we have been developing Solr score configuration in Plone. After a short discussion with witsch we have decided to contribute our efforts and merge everything to collective.solr branch. This is just a simple configuration panel with additional score query builder. Every score-boost entry has 3 fields: index, value and score. In current implementation if you leave value empty - it will be populated with SearchableText index value - when building the query. This approach allows flexibility our customer needs.

Let's assume you want to sort results as follow:

• Description has a query boost 10.0
• portal_type=Document has a query boost 15.0
• review_state=published has a query boost 20.0

In this way you can boost Description index (for which the value will be taken from SearchableText) and portal_type index (for which you can define the value manualy) at the same time.

to-do: we would like to add as an option Solr score explanation in search results (for users who want to know why certain document has certain score).

We have found also some problems with Lucene proximity algorithm which can give some problems (it should be configurable in Solr 1.4.0). 

Description:%(searchterm)s^10 Title:%(searchterm)s^20 portal_type:Folder^10 portal_type:Document^30 review_state:published^100