This is an average star rating custom field.
This has been posted as an example of what can be achieved using the latest version of the Custom Fields add-on.
This custom field works in conjunction with the Star Rating for Custom Fields field. When that field is imported as a post field, this field can be imported as a thread field or a resource field and will then show the average rating of all the post field ratings.
Alternatively, this field will also work with any other custom post field that gives the user a choice of a number between 0 and 5.
When editing a thread, this custom field will give you a choice of which custom post field you would like to find the average rating of. If you would rather your users did not see this, you can set a default value in the Admin Control Panel and then remove the ability for users to edit this field.
Thanks to oloman for contributing to the development of this resource.