Personally, I have my doubts about this actually working and I think
others do too. It's in there in Lucene, but I don't know if it makes
sense. Logically speaking, I just don't see how it makes sense to
compare different queries results, but maybe I'm just short-sighted.
I'd certainly welcome some references to research on the "why" part of
it.
On Feb 28, 2009, at 3:17 AM, Michael Stoppelman wrote:
I was just reading the Similarity javadocs (
http://lucene.apache.org/java/2_4_0/api/org/apache/lucene/search/Similarity.html#formula_queryNorm)
and I thought this might be relevant to your issue.
From the javadoc:
*queryNorm(q) * is a normalizing factor used to make scores between
queries
comparable. This factor does not affect document ranking (since all
ranked
documents are multiplied by the same factor), but rather just
attempts to
make scores from different queries (or even different indexes)
comparable.
This is a search time factor computed by the Similarity in effect at
search
time.
M
On Wed, Feb 25, 2009 at 10:48 PM, Michael Stoppelman <stop...@gmail.com
>wrote:
Hi Ken,
I found this post on the Lucene documentation page:
http://wiki.apache.org/lucene-java/LuceneFAQ#head-912c1f237bb00259185353182948e5935f0c2f03
In practice you sometimes need to have a cut-off or boost factor post
tf-idf scoring. The way I've been going about it is by picking
values and
seeing if the results are better.
I'm sure there is a deep information theory problem there.
M
On Wed, Feb 25, 2009 at 8:38 AM, Ken Williams <
ken.willi...@thomsonreuters.com> wrote:
Hi all,
I didn't get a response to this - not sure whether the question was
ill-posed, or too-frequently-asked, or just not interesting. But if
anyone
could take a stab at it or let me know a different place to look,
I'd
really
appreciate it.
Thanks,
-Ken
On 2/20/09 12:00 PM, "Ken Williams"
<ken.willi...@thomsonreuters.com>
wrote:
Hi,
Has there been any work done on getting confidence scores at
runtime, so
that scores of documents can be compared across queries? I found
one
reference in the mailing list to some work in 2003, but couldn't
find
any
follow-up:
http://osdir.com/ml/jakarta.lucene.user/2003-12/msg00093.html
Thanks.
--
Ken Williams
Research Scientist
The Thomson Reuters Corporation
Eagan, MN
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