Xapian discuss - Jun 2008 - Change document relevance on user feedback

Hello,
before I use xapian for my project, I would like if it is possible to do the
following (Have read a lot of the archive mailing list but I am not sure I
got it right):
the user is show a set of result for a given query
the user select a document and click on to say if the document is relevant.
if it does can I update the relevance of that document for the terms used?
Thanks in advance
Benjamin

Benjamin Hille wrote:
> Hello,
> before I use xapian for my project, I would like if it is possible to do
the
> following (Have read a lot of the archive mailing list but I am not sure I
> got it right):
> the user is show a set of result for a given query
> the user select a document and click on to say if the document is relevant.
> if it does can I update the relevance of that document for the terms used?
Yes, this is supported by Xapian.

Briefly, the API allows you to supply a relevance set to the match 
process (which is a set of documents marked as relevant).  It also 
allows a relevance set to be used to calculate a set of expansion terms 
(ie, terms which might be useful to add to the query to find documents 
similar to those marked as relevant).


http://xapian.org/search.php supports this method of feedback - each 
result has a checkbox - if you click the checkbox and then click the 
"Search" button again, the termweights will be adjusted based on the
new
information, and results will be recalculated.  For small queries, this 
often doesn't produce much direct improvement, because only the weights 
of the terms are modified, so two documents which match the same terms 
will often remain ranked in the same order, even if only one of the 
documents was relevant.

However, xapian also supports calculation of a list of suggested 
"expansion" terms, which are displayed at the top of the screen in
this
case.  These terms will also be updated based on the relevance 
information.  You can click the boxes by these terms to add them to the 
query, but an alternative implementation is to simply add such terms 
automatically to the query ("behind the scenes", so that the user 
doesn't see them), which is more limited, but may be an easier interface 
for users.

-- 
Richard

---------- Forwarded message ----------
From: Benjamin Hille <benjamin at hille.me.uk>
Date: Thu, Jun 12, 2008 at 4:56 PM
Subject: Re: [Xapian-discuss] Change document relevance on user feedback
To: Richard Boulton <richard at lemurconsulting.com>


Yes, this is supported by Xapian.
>
Excellent I thought so.
>
> Briefly, the API allows you to supply a relevance set to the match process
> (which is a set of documents marked as relevant).  It also allows a
> relevance set to be used to calculate a set of expansion terms (ie, terms
> which might be useful to add to the query to find documents similar to
those
> marked as relevant).
>
do you use the RSet class to say "this Document is more relevant for this
query" ?
>
>
> http://xapian.org/search.php supports this method of feedback - each
> result has a checkbox - if you click the checkbox and then click the
> "Search" button again, the termweights will be adjusted based on
the new
> information, and results will be recalculated.  For small queries, this
> often doesn't produce much direct improvement, because only the weights
of
> the terms are modified, so two documents which match the same terms will
> often remain ranked in the same order, even if only one of the documents
was
> relevant.
>
> However, xapian also supports calculation of a list of suggested
> "expansion" terms, which are displayed at the top of the screen
in this
> case.  These terms will also be updated based on the relevance information.
>  You can click the boxes by these terms to add them to the query, but an
> alternative implementation is to simply add such terms automatically to the
> query ("behind the scenes", so that the user doesn't see
them), which is
> more limited, but may be an easier interface for users.

On the xapian search page when the user click the box "this document is
relevant", how do you update the index to reflect this?

Thanks for your helpl
Benjamin

>
>
> --
> Richard
>

>
>> the user is show a set of result for a given query
>> the user select a document and click on to say if the document is
>> relevant.
>> if it does can I update the relevance of that document for the terms
used?
>>
>
> Yes, this is supported by Xapian.
>
> Briefly, the API allows you to supply a relevance set to the match process
> (which is a set of documents marked as relevant).  It also allows a
> relevance set to be used to calculate a set of expansion terms (ie, terms
> which might be useful to add to the query to find documents similar to
those
> marked as relevant).
>
I cannot find anywhere in API if it is possible to store back the relevance
into the database. It looks like RSet does not write back into the db when
you add a document to it. What really I need is once a user A as choosen the
document as relevant for a query the same query by user B should have the
document choosen by A as relevant.

Benjamin

On Fri, Jun 13, 2008 at 04:55:51PM +0100, Benjamin Hille
wrote:
> I cannot find anywhere in API if it is possible to store back the relevance
> into the database. It looks like RSet does not write back into the db when
> you add a document to it. What really I need is once a user A as choosen
the
> document as relevant for a query the same query by user B should have the
> document choosen by A as relevant.
Note that it may not be true that a document which is relevant to a
query for user A is also relevant to the exact same query for user B.

Disambiguation pages on wikipedia nicely illustrate one reason for this
- a word or phrase can have multiple meanings, and different users may
be looking for different meanings which have the same expression.  For
example, a query for "stock" could mean many things:

http://en.wikipedia.org/wiki/Stock_(disambiguation)

Even if users are actually expressing the same meaning, they may not
like the same pages.  A Java guru might search for a standard class name
to check some obscure detail and want reference material; a Java novice
might search for the same class, but want tutorials.

Cheers,
    Olly